The "./iso" was the trouble for me. I had already put the contents of the ISO into a directory under my home folder,thinking maybe it was a permission problem,but you'll HAVE to do this because you cant write the corrected file back to an already burned CD-ROM. I did the following (again,from a dir under my home folder):
I started by opening Packages.TXT.gz with Engrampa,
extracted the TXT file to Geany(right click the file in Engrampa and select "Open With..."),
did a search and replace( "./iso/" -> "./" ),
rolled it back to the archive(when I saved the file in Geany, Engrampa asked if I wanted to update the archive,select YES),
reran Gslapt,
and it WORKED!!
THANK YOU!! laprjns, for pointing me down the right path!!