Here's the 6DOF camera code from the forums. I've moved the variable declarations/functions around to make it compile, and changed the values shown on the screen slightly to display mouseaxis results.
Watch the figures returned by mouseaxis and tell me if it consistently reflects what you're doing with the mouse. If it does, you're getting different results to me. I get numbers sometimes, 0 other times (when I should be getting mouse movement values). Compare the difference if you use the mouseaxis near the top of the main routine against using the mouseaxis calls right before showscreen command. They SHOULD behave the same but they don't and therefore it's a bug as where it's called from in relation to X_MAKE3D, X_MAKE2D and SHOWSCREEN, should not impact the values returned!
Use the mouse buttons and see if it always changes the camera rotation like it should - it's inconsistent for me. (Note that the original code divided the mouseaxis returned values by 10, I took that out to really show when it was and wasn't working.)
Prove me wrong that MOUSEAXIS ISN'T broken!

// --------------------------------- //
// Project: 6DOFCam_lib
// Start: Thursday, November 19, 2009
// IDE Version: 7.177
//
CONSTANT rad = 3.1415926535/180
TYPE Tquaternion
w#
x#
y#
z#
ENDTYPE
TYPE Tcamera
//position
x#
y#
z#
//look vector
lx#
ly#
lz#
//up vector
ux#
uy#
uz#
//right vector
rx#
ry#
rz#
FOV#
aspect#
nearClip#
farClip#
ENDTYPE
LOCAL cam1 AS Tcamera
LOCAL speed# = .01
LOCAL xv#, yv#, zv#, p#=0, r#=0, y#=0
LOCAL mx%, my%, mw%, mba%, mbb%
// --------------------------------- //
// Project: 6DOFCam_test
// Start: Thursday, November 19, 2009
// IDE Version: 7.177
cam1.x# = 0
cam1.y = 0
cam1.z = 0
cam1.lx = 0
cam1.ly = 0
cam1.lz = -1
cam1.ux# = 0
cam1.uy# = 1
cam1.uz# = 0
cam1.rx = 1
cam1.ry = 0
cam1.rz = 0
cam1.FOV = 45
cam1.aspect = 1024/768
cam1.nearClip = .01
cam1.farClip = 5000
WHILE TRUE
MOUSESTATE mx, my, mba, mbb
mx = MOUSEAXIS(0)
my = -MOUSEAXIS(1)
X_6DOFCAMERA(cam1)
//Linear Velocity Dampening (SPACE)
IF KEY(57)
xv = xv * .95
yv = yv * .95
zv = zv * .95
ENDIF
//Angular Velocity Dampening (CTRL)
IF KEY(29)
r = r * .95
p = p * .95
y = y * .95
ENDIF
//Accelerate Forward (W)
IF KEY(17)
xv = xv + (cam1.lx - cam1.x) * speed
yv = yv + (cam1.ly - cam1.y) * speed
zv = zv + (cam1.lz - cam1.z) * speed
ENDIF
//Accelerate Backward (S)
IF KEY(31)
xv = xv - (cam1.lx - cam1.x) * speed
yv = yv - (cam1.ly - cam1.y) * speed
zv = zv - (cam1.lz - cam1.z) * speed
ENDIF
//Accelerate Left (A)
IF KEY(30)
xv = xv + (cam1.rx - cam1.x) * speed
yv = yv + (cam1.ry - cam1.y) * speed
zv = zv + (cam1.rz - cam1.z) * speed
ENDIF
//Accelerate Right (D)
IF KEY(32)
xv = xv - (cam1.rx - cam1.x) * speed
yv = yv - (cam1.ry - cam1.y) * speed
zv = zv - (cam1.rz - cam1.z) * speed
ENDIF
//Accelerate Down (F)
IF KEY(33)
xv = xv + (cam1.ux - cam1.x) * speed
yv = yv + (cam1.uy - cam1.y) * speed
zv = zv + (cam1.uz - cam1.z) * speed
ENDIF
//Accelerate Up (R)
IF KEY(19)
xv = xv - (cam1.ux - cam1.x) * speed
yv = yv - (cam1.uy - cam1.y) * speed
zv = zv - (cam1.uz - cam1.z) * speed
ENDIF
// change IF the left mouse button is pressed
IF mba = 1
//Pitch mouse up AND
p = p + my
//Yaw
y = y + mx
ELSEIF mbb = 1
//Roll with right mouse button
r = r + mx
ENDIF
cam1.x = cam1.x + xv
cam1.y = cam1.y + yv
cam1.z = cam1.z + zv
cam1.lx = cam1.lx + xv
cam1.ly = cam1.ly + yv
cam1.lz = cam1.lz + zv
cam1.rx = cam1.rx + xv
cam1.ry = cam1.ry + yv
cam1.rz = cam1.rz + zv
cam1.ux = cam1.ux + xv
cam1.uy = cam1.uy + yv
cam1.uz = cam1.uz + zv
debug_view(0,0,0,100,RGB(255,255,0),RGB(255,0,255),RGB(0,255,255))
camera_roll(cam1,r)
camera_pitch(cam1,p)
camera_yaw(cam1,y)
X_MAKE2D
PRINT "mx = "+mx,10,90
PRINT "my = "+my,10,100
PRINT "Cam Pitch = "+p,10,110
PRINT "Cam Yaw = "+y,10,120
PRINT "Cam Roll = "+r,10,130
// mx = MOUSEAXIS(0)
// my = -MOUSEAXIS(1)
SHOWSCREEN
WEND
FUNCTION quaternion_normalize AS Tquaternion: tmpQ AS Tquaternion
LOCAL mag# = SQR(tmpQ.w*tmpQ.w+tmpQ.x*tmpQ.x+tmpQ.y*tmpQ.y+tmpQ.z*tmpQ.z)
LOCAL q AS Tquaternion
q.w = tmpQ.w / mag
q.x = tmpQ.x / mag
q.y = tmpQ.y / mag
q.z = tmpQ.z / mag
RETURN q
ENDFUNCTION
FUNCTION quaternion_conj AS Tquaternion: tmpQ AS Tquaternion
LOCAL q AS Tquaternion
q.w = -tmpQ.w
q.x = -tmpQ.x
q.y = -tmpQ.y
q.z = -tmpQ.z
RETURN q
ENDFUNCTION
FUNCTION quaternion_mult AS Tquaternion: lhs AS Tquaternion, rhs AS Tquaternion
LOCAL q AS Tquaternion
q.w = lhs.w * rhs.w - lhs.x * rhs.x - lhs.y * rhs.y - lhs.z * rhs.z
q.x = lhs.w * rhs.x + lhs.x * rhs.w + lhs.y * rhs.z - lhs.z * rhs.y
q.y = lhs.w * rhs.y - lhs.x * rhs.z + lhs.y * rhs.w + lhs.z * rhs.x
q.z = lhs.w * rhs.z + lhs.x * rhs.y - lhs.y * rhs.x + lhs.z * rhs.w
RETURN q
ENDFUNCTION
FUNCTION camera_advance: cam AS Tcamera, d#
LOCAL xt#, yt#, zt#
xt = (cam.lx - cam.x) * d
yt = (cam.ly - cam.y) * d
zt = (cam.lz - cam.z) * d
cam.x = cam.x + xt
cam.y = cam.y + yt
cam.z = cam.z + zt
cam.ux =cam.ux + xt
cam.uy =cam.uy + yt
cam.uz =cam.uz + zt
cam.rx =cam.rx + xt
cam.ry =cam.ry + yt
cam.rz =cam.rz + zt
cam.lx =cam.lx + xt
cam.ly =cam.ly + yt
cam.lz =cam.lz + zt
ENDFUNCTION
FUNCTION camera_strafe: cam AS Tcamera, d#
LOCAL xt#, yt#, zt#
xt = (cam.rx - cam.x) * d
yt = (cam.ry - cam.y) * d
zt = (cam.rz - cam.z) * d
cam.x = cam.x + xt
cam.y = cam.y + yt
cam.z = cam.z + zt
cam.ux = cam.ux + xt
cam.uy = cam.uy + yt
cam.uz = cam.uz + zt
cam.rx = cam.rx + xt
cam.ry = cam.ry + yt
cam.rz = cam.rz + zt
cam.lx = cam.lx + xt
cam.ly = cam.ly + yt
cam.lz = cam.lz + zt
ENDFUNCTION
FUNCTION camera_rise: cam AS Tcamera, d#
LOCAL xt#, yt#, zt#
xt = (cam.ux - cam.x) * d
yt = (cam.uy - cam.y) * d
zt = (cam.uz - cam.z) * d
cam.x = cam.x + xt
cam.y = cam.y + yt
cam.z = cam.z + zt
cam.ux = cam.ux + xt
cam.uy = cam.uy + yt
cam.uz = cam.uz + zt
cam.rx = cam.rx + xt
cam.ry = cam.ry + yt
cam.rz = cam.rz + zt
cam.lx = cam.lx + xt
cam.ly = cam.ly + yt
cam.lz = cam.lz + zt
ENDFUNCTION
FUNCTION camera_roll: cam AS Tcamera, a#
LOCAL qUp AS Tquaternion
qUp.w = 0
qUp.x = cam.ux - cam.x
qUp.y = cam.uy - cam.y
qUp.z = cam.uz - cam.z
LOCAL qRight AS Tquaternion
qRight.w = 0
qRight.x = cam.rx - cam.x
qRight.y = cam.ry - cam.y
qRight.z = cam.rz - cam.z
LOCAL qRot AS Tquaternion
qRot.w = COS(a * rad/2)
qRot.x = (cam.lx - cam.x) * SIN(a * rad/2)
qRot.y = (cam.ly - cam.y) * SIN(a * rad/2)
qRot.z = (cam.lz - cam.z) * SIN(a * rad/2)
LOCAL W AS Tquaternion,W1 AS Tquaternion,W2 AS Tquaternion
W1 = quaternion_mult(qRot,qUp)
W2 = quaternion_conj(qRot)
W = quaternion_mult(W2,W1)
W = quaternion_normalize(W)
cam.ux = W.x + cam.x
cam.uy = W.y + cam.y
cam.uz = W.z + cam.z
// W = quaternion_mult(quaternion_mult(qRot,qRight), quaternion_conj(qRot)) <<< This does not work?!?!
W1 = quaternion_mult(qRot,qRight)
W2 = quaternion_conj(qRot)
W = quaternion_mult(W2,W1)
W = quaternion_normalize(W)
cam.rx = W.x + cam.x
cam.ry = W.y + cam.y
cam.rz = W.z + cam.z
ENDFUNCTION
FUNCTION camera_pitch: cam AS Tcamera, a#
LOCAL qUp AS Tquaternion
qUp.w = 0
qUp.x = cam.ux - cam.x
qUp.y = cam.uy - cam.y
qUp.z = cam.uz - cam.z
LOCAL qLook AS Tquaternion
qLook.w = 0
qLook.x = cam.lx - cam.x
qLook.y = cam.ly - cam.y
qLook.z = cam.lz - cam.z
LOCAL qRot AS Tquaternion
qRot.w = COS(a * rad/2)
qRot.x = (cam.rx - cam.x) * SIN(a * rad/2)
qRot.y = (cam.ry - cam.y) * SIN(a * rad/2)
qRot.z = (cam.rz - cam.z) * SIN(a * rad/2)
LOCAL W AS Tquaternion,W1 AS Tquaternion,W2 AS Tquaternion
W1 = quaternion_mult(qRot,qUp)
W2 = quaternion_conj(qRot)
W = quaternion_mult(W2,W1)
W = quaternion_normalize(W)
cam.ux = W.x + cam.x
cam.uy = W.y + cam.y
cam.uz = W.z + cam.z
W1 = quaternion_mult(qRot,qLook)
W2 = quaternion_conj(qRot)
W = quaternion_mult(W2,W1)
W = quaternion_normalize(W)
cam.lx = W.x + cam.x
cam.ly = W.y + cam.y
cam.lz = W.z + cam.z
ENDFUNCTION
FUNCTION camera_yaw: cam AS Tcamera, a#
LOCAL qRight AS Tquaternion
qRight.w = 0
qRight.x = cam.rx - cam.x
qRight.y = cam.ry - cam.y
qRight.z = cam.rz - cam.z
LOCAL qLook AS Tquaternion
qLook.w = 0
qLook.x = cam.lx - cam.x
qLook.y = cam.ly - cam.y
qLook.z = cam.lz - cam.z
LOCAL qRot AS Tquaternion
qRot.w = COS(a * rad/2)
qRot.x = (cam.ux - cam.x) * SIN(a * rad/2)
qRot.y = (cam.uy - cam.y) * SIN(a * rad/2)
qRot.z = (cam.uz - cam.z) * SIN(a * rad/2)
LOCAL W AS Tquaternion,W1 AS Tquaternion,W2 AS Tquaternion
W1 = quaternion_mult(qRot,qRight)
W2 = quaternion_conj(qRot)
W = quaternion_mult(W2,W1)
W = quaternion_normalize(W)
cam.rx = W.x + cam.x
cam.ry = W.y + cam.y
cam.rz = W.z + cam.z
W1 = quaternion_mult(qRot,qLook)
W2 = quaternion_conj(qRot)
W = quaternion_mult(W2,W1)
W = quaternion_normalize(W)
cam.lx = W.x + cam.x
cam.ly = W.y + cam.y
cam.lz = W.z + cam.z
ENDFUNCTION
FUNCTION X_6DOFCAMERA: cam AS Tcamera
X_MAKE3D cam.nearClip, cam.farClip, cam.FOV
X_CAMERAUP cam.x - cam.ux, cam.y - cam.uy, cam.z - cam.uz
X_CAMERA cam.x, cam.y, cam.z, cam.lx, cam.ly, cam.lz
ENDFUNCTION
FUNCTION debug_view: x, y, z, crad, rgb1, rgb2, rgb3
LOCAL rad, x1, y1, j, x2, y2
y1=SIN(0)*crad
x1=COS(0)*crad
FOR j=4 TO 360 STEP 4
y2=SIN(j)*crad
x2=COS(j)*crad
X_LINE x+x1,y+y1,z , x+x2,y+y2,z,0.1,rgb1
X_LINE x+x1,y+0,y1+z, x+x2,y+0,y2+z,1,rgb2
X_LINE x+0,y+x1,y1+z, x+0,y+x2,y2+z,1,rgb3
x1=x2
y1=y2
NEXT
X_DOT x,y,z,10,rgb1
X_DRAWAXES x+crad,y,z
X_DRAWAXES x-crad,y,z
X_DRAWAXES x,y+crad,z
X_DRAWAXES x,y-crad,z
X_DRAWAXES x,y,crad+z
X_DRAWAXES x,y,-crad+z
X_PRINT "RIGHT X+",x+crad,y,z,0
X_PRINT "LEFT X-",x-crad,y,z,0
X_PRINT "UP Y+",x,y+crad,z,0
X_PRINT "DOWN Y-",x,y-crad,z,0
X_PRINT "OUT Z+",x,y,crad+z,0
X_PRINT "IN Z-",x,y,-crad+z,0
X_SETTEXTURE -1, -1
ENDFUNCTION