I got the same problems (setup the pref's every startup; could'nt download to the desktop or another folder, which is'nt the sharing folder; furthermore i could'nt use the german user surface).
I read about this problem in other forums too.
May i got a workaround, terribly i can't exactly remember, how i did it (means the steps order).
The 2.6.5 version didn't known this problems, so i got the idea to use these preferences.
In every case it has to do with the
"~/library/preferences/.limewire/limewire.props"
document( invisible), which should be used from the 2.6.5 (possibly previous versions too ).
I think it was this way:
1. I uninstalled the whole old limewire by using the "Uninstall LimeWire" application.
2. I installed the 2.6.5 , started it one time including doing the pref's setup, then I quit it.
3. I installed the 2.7.3, started it and it used the 2.6.5 pref's without any problem.
4. I removed the whole 2.6.5 folder and doc's except the above mentioned, the
"~/library/preferences/LimeWire_Installer.plist"
and the
"~/library/preferences/LimeWire.plist"
("~" means your home directory).
Do this step by drag and drop !!!.
Afterwards the 2.7.3 worked and started without problems till now.
Maybe I exchanged step 3 and 4, i don't know anymore, so I please you to try different orders of the steps above to get the ultimate solution.
Unfortunately I got problems with my mail-account this time, so it would be nice, if anybody posts in this forum, if it works.

Hope, it helps you, folks.
( sorry for my terrible english)

hey...i tried this in a way...for me...it did not work...i uninstalled the old version, downloaded new one, and then deleted those files except that one...then i downloaded it again and it keeps telling me to set up and all...i dont kno how you did it man.

Hello

i try to explain it again (sorry about my bad english, i'm from germany).
1. step: delete the whole limewire ( means all LW versions), favourable by using the uninstaller
2.step : install the 2.6.5 limewire, start it one time and set your preferences, then quit it and delete the limewire folder by drag and drop
(nothing furthermore is here necessary, because your preferences are saved in another folder)
3. step: install the 2.7.3 limewire, it uses your setted preferences, everything should be right

I tried this way again and it works.
If this doesn't help, probably it would be better to use the 2.6.5 version until the bug is fixed by limewire.

Here you find the whole download archive of limewire:
http://www3.limewire.com/download/

Auf Wiedersehen, bis nächstes Mal.

Look at the posting labelled "I found an answer for me!" in the "~/Limewire forgets all my preferences" thread.