I have XP and the only way I can get Limewire to work with Optimum is to Uninstall it.

Make sure that Limewire is closed. I go to:
1.Start
2.All Programs
3.Limewire
and then I select
4.Uninstall.

After I uninstall Limewire I go to:
1.Start
2.Search
3.All files and folders
and then I type in Limewire and thin hit Search.

I then delete everything about Limewire and restart my PC.

I then reinstall the program and it works for a few days and then I do it all again. A real pain in the a$$ but it gets the job done.