The bug report mentioned earlier has a fix already in place for this. You can check it out or just use your workaround until the next octave release.
If you want to just fix it and avoid the workaround, you only need to make a couple small changes to one of pkg's m files. On my system that file is located at
lines 130 and 133 need to have quotation marks added as shown in this patch:
you could also save that file and replace the one in your copy of octave if you don't want to edit things manually.