Try deleting your LW Preferences folder whilst LW is closed; instructions here:
Fixes for Limewire If that doesn't work then update your Java to version 1.5 (see previous link for downld link!)
If this doesn't fix it then perhaps there's a problem with your shortcuts. Go directly to the LW program folder & open LW directly. If it opens it means your shortcuts are corrupt. So delete them & recreate them.