No, I don't think it is a permissions file. I am familiar with chmod, and I've used chmod and chown to set permissions and ownership of these directories. Specifically\, I've:
limeuser@beast# su -
root@beast# echo usrlocal:x:555:limeuser >> /etc/group
root@beast# chown -R root:usrlocal /usr/local/LimeWire
root@beast# chmod -R g+rw /usr/local/LimeWire
root@beast# chmod g+x /usr/local/LimeWire/runlime.sh
root@beast# echo media:x:556:limeuser >> /etc/group
root@beast# chown -R root:media /usr/share/media
root@beast# chmod -R g+rw /usr/share/media

Leaving:
root@beast# ls -lad /usr/local/LimeWire
drwxrwxr-x 3 root usrlocal 4096 Nov 7 00:12 /usr/local/LimeWire
root@beast# ls -lad /usr/share/media
drwxrwxr-x 5 root media 8192 Nov 6 20:16 /usr/share/media

In 1.7 there were Incomplete and Shared directories that I also changed in 1.7c... in 1.8 there's just the $LIMEWIRE/lib directory.

And I've set the save directory to /usr/share/media. And I'm in the proper groups before I execute runlime.sh:root@beast#exit
limeuser@beast#groups
limeuser usrlocal media
Nonetheless, I cannot get any successful download as user limeuser unless I change the save directory to /home/limeuser (which BTW means to me that the Incomplete directory, wherever that's gone, isn't the issue).

lol