Hello all Mach4 gurus!! 

I have a bit of a head scratcher, for me at least.  It seems simple but I am having trouble root causing my issue.

I tried a simple GCode script first and it was successful.  For example:

G10 L2 P1 X123.3844 Y492.9423 Z-29.9250
G10 L2 P2 X273.3844 Y492.9423 Z-29.9250
G10 L2 P3 X423.3844 Y492.9423 Z-29.9250
G54
M98 P1234
G55
M98 P1234
G56
M98 P1234
M5
M30
O1234
G0 X10
G0 Y10
G0 X0
GO Y0
M99

This runs the "loop" successfully.

However if I add my job Gcode, with ~ 85,000 lines within O1234 the program does not recognize the M99  command.  The job runs all the code within O1234 but stops at the last command line just before the M99 call.  Therefore it does not return to the main program, adjust the tooling offset and repeat the O1234 code, like it should.

Am I missing something really small and fundamental?

Thanks a bunch!

Any chance that the code that you inserted does not have a final carriage return after the M99?

Thanks Steve.  Correct.  The line M99 is on does NOT have a carriage return.  It is in fact the last line.  Is this the small fundamental issue that I am missing!? 

I'll adjust accordingly and try it again.

Thanks @Steve Stallings.  Problem solved!