Can other people in the dorm use p2p (LW or other apps) without a problem? Maybe the school's started blocking p2p...you should check on that.

Double check your Windows firewall config. Are you sure there's not a McAfee firewall?
Try changing ports: in LW tools > options > advanced > firewall config. Change LW's listening port to 64049 > Apply > ok. You can also try other ports in the range of 49152 - 65535.

Delete LW's preferences folder when LW's properly closed. See point 3 here & also point 2 if you've used older versions of LW in the past (there could be a folder in either location).
Fixes for LimeWire
This will kill all of your settings within options, you'll have to go back through afterwards & reset things. If you're not sure of your settings, go through LW's tools > options & write them all down, so that you can reset things later.

You could also try this version of Java. Download the JRE offline installer & remove any other Java versions before you install this one.
Archive: Download Java 2 Platform Standard Edition (J2SE) 5.0 Update 11