See if it's related to any of these: 1.
The way to fix the Blank screen on startup, 2.
GeoForce 3D setting, 3.
Fix for LW interface blank spots problem
What version of Java are you using?
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.) This is often wise after updating to Pro.