One issue is that you need to add an empty space after "StimType" in each of the following 7 lines:
-gltLabel 1 '0back_RT' -gltCode 1 'StimType: 1*0back meanRTacrossrun :' \
-gltLabel 2 '1back_RT' -gltCode 2 'StimType: 1*1back meanRTacrossrun :' \
-gltLabel 3 '2back_RT' -gltCode 3 'StimType: 1*2back meanRTacrossrun :' \
-gltLabel 4 '3back_RT' -gltCode 4 'StimType: 1*3back meanRTacrossrun :' \
-gltLabel 5 '3v0_RT' -gltCode 5 'StimType: 1*3back -1*0back meanRTacrossrun :' \
-gltLabel 6 '2v0_RT' -gltCode 6 'StimType: 1*2back -1*0back meanRTacrossrun :' \
-gltLabel 7 '1v0_RT' -gltCode 7 'StimType: 1*1back -1*0back meanRTacrossrun :' \
If you're interested in comparing the three stimulus types (it looks like you're not), you may need to center the RT values properly if you believe RT differs across the stimulus types.
Gang
