Try first writing down the entire line somewhere, then delete that entire line. Then, type it back in. This might discover some sort of non-printable machine character was loaded in with the program.
How are you loading programs in, btw? Not with floppies, I hope. BTW, are you checking your program first by running it in graphics mode?
Another test: leave the bad program in memory and load in a second copy of the program (alter the name and number). Then try running the second copy. This might discover a bad bit in the ram where the first copy of the program is stored.
I dunno, just a couple of things I would try
First you get good, then you get fast. Then grouchiness sets in.
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)