Make sure you have a minimum of Java 1.5 then. Also make sure you have at least 500 MB ram, also make sure you have several GB free for VM & downloads.

Also consider 1. Tip: Purge the Downloads Queue!, & also 2. Disabling your Ultrapeer capabilities: Go to LW's menu bar, Tools>Options>Speed & uncheck option & press apply button.

If none of that works then try deleting your LW Preferences folder whilst LW is closed; instructions here: Point #2 & 3 in Fixes for Limewire (sample image included at bottom of page.)