Starting with VFP 6, you won't be able to compile a prg or form with syntax errors and this is an improvement by all means because it took out some 'Syntax error' runtime crashes you would potentially have ended up with.

I ran into a lot of Clipper and Xbase code that used to run fine in FoxPro 2.X and VFP 3.0 but won't compile in VFP 6 and 7.