Hey,
I know this is a common problem that people cant install some mods, or cant install *.xpi files etc. However, nobody seems to have given an exact error they get. I installed PFF onto my personal drive in college (I cant install anything anywhere else). However, on launching an extension or skin install half way through the procedure this error appears;
"Firefox could not install the file at [URL to extension] because: script error".
Sometimes its installed after I re-boot tho.
Any ideas? Its the same error when I go to "File > Open" and launch the xpi file I saved on the PC.