Do you mean when you "load GCode" ANY program you load comes up with this error message, or is it just a particular one.
Can you load any GCode programs, even those from else where, or are you using a CAD/CAM program to generate GCode.
The error message generally is telling you that in line *** there is an error - something the GCode translator does not recognise.
Normally this is when you use, e.g. an O (ooo) instead of a 0 (zero) or similar fault, or you have used a unrecognised command.
Check the appropriate line and see if you can see an obvious fault. It may be a comment line or something similar.
You could write you own program and try and load it e.g. G0X0Y0 would suffice - call it "test" or something like that and see if the machine takes it.