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.)
Although the blank screen can sometimes be fixed by jumping back to Java 1.4.2, actually Java 1.5 is really required for LW 4.12 or later. Did you check your graphic card settings? You prolly saw these links but I'll repeat anyway: 1.
The way to fix the Blank screen on startup, 2.
GeoForce 3D setting, 3.
Fix for LW interface blank spots problem