1. 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.)
2. Try reverting your Java. Remove all versions of Java. Then install this one:
Java 1.5 (take the JRE)
3. Don't use the same port as the other computer to connect thru.
What model & brand of router are you using?