HI MrT, I think the problem it's SDL, in this Linux when I try to run something compiled to Linux says all you comment, but here comment something SDL 1.2 it's old... Perhaps I don't know Ubuntu in default uses SDL 2.0...
About the depth of bits here put the same I think Linux try to use in 16bpp.
I don't think this have to be too much problem, just yesterday I try an AGK example, a 3d scene compiled and runs fine, Ok AGK and GLbasic don't have nothing similar but if this guys make runs in Linux , Gernot sure too!!!!