It's been a long time since I used Limewire on OS 8.6, so sorry if the next suggestions don't help. (BTW, what program do you normally use to play your .mp3's?)
-Does your Limewire options have a checkbox to use quicktime, or something like that? That would be the easiest fix.
-You can just drag the mp3's from the folder on the hard disk to the Quicktime MoviePlayer. This might work too if the files are differrent audio formats (some get renamed--try deleting the extension)
--To set the doubleclick for mp3's, go to the Control Panel "File Exchange," scroll down the list to select ".mp3," then hit the "change" button to choose the app you want.
Well, hope these guesses help. Let me know what works.