Hi-
That is a bug that I seem to have introduced into the QC part at the end of afni_proc.py (which occurs in the case when 1 stim is used). I have now squashed it and committed the change---thanks for mentioning this.
We will do a build soon to update the binaries, but I can send you a copy of the updated file, as well as instructions for running the final QC part, if you would like.
--pt