Apparently there's a warning in line 411 of setup_6581.asm :D Which line is that in your file? What this (which is not a MIOS error but a compiler warning btw) tells you is that some value is assigned to some variable, with the value being out of range. For instance if you had an "unsigned char" = 1 Byte = 0-255 and assigned 258 to it, you'd get that error. So, what's in line 411 of your setup_6581.asm?