From the points you make, I assume you're a Mac OS8-9.x user.

1. I also get the non-fatal error in the installation log, but it doesn't seem to affect LW's operation.

2. The Mac OS8-9 version of Limewire doesn't have an internal player like the others so you need to download an external mp3 player like iTunes, Audion or MacAmp.

3. When you get a player installed, forget about trying to launch them from LW or double clicking them in the Finder as there are very often configuration problems. The best way is to open your shared folder and DRAG them directly onto the mp3 player. Or better yet, copy them all to a separate music folder and select this folder as a playlist within your chosen mp3 player.