AS Hood said before, you need to get the post to add G91.1.
I'd recommend adding it after the G20 G90 G64 G40 line, like this, as it shouldn't be on the same line as G90 (one will be ignored.)
G20 G90 G64 G40
G91.1
G0 Z0.125
( T0 : 0.01 )
T0 M6
( Profile1 )
I've never used CamBam either, though, so can't tell you how it's done.