I changed the offending code in this routine...
FOREACH m IN self.m[]
m.combined% = ASL((m.alpha#)*255,24)+ASL(m.blue#*255,16)+ASL(m.green#*255,8) + m.red#*255
NEXT
to...
FOREACH mat IN self.m[]
mat.combined% = ASL((mat.alpha#)*255,24)+ASL(mat.blue#*255,16)+ASL(mat.green#*255,8) + mat.red#*255
NEXT
...but still got eh error "error : GPC0007 wrong argument type" at the FOREACH line, even though I changed "m" to "mat", only within these lines?!?!