Did you use the english installer or the international (multilingual) installer. These are different in the respect the latter forces LW to use an earlier version of Java which is not really sufficient in many cases.

Delete your LW Preferences folder. In fact, why not follow these hints (your java may be an older version): Fixes for Limewire

If they don't work, try the beta 4.3.3 which overcomes some bugs within LW 4.2 : http://www.limewire.com/english/content/beta.shtml