I get the same message when I try and open a gcode in mach3.."bad character used line 0"     and there is no picture.  The code looks like this...   
code:
(cutoff)
auto optimization=1
climb cut=0
code snip=1
comment=
...so on and so forth
 This is the same for both new drawings from draftsight and previous files that I had already cut.   I am new to cnc and bought a viper last fall.   It came with draftsight, sheetcam and mach3.   Their tech dept won't respond to my questions so I am on my own and pretty frustrated. The sheetcam and mach3 were already loaded on the machine...so...I don't have a cd to reload mach3...HELP   thanks