Usually nowadays yes, schools, colleges, etc. block or filter p2p programs. Here's an example of how a p2p bandwidth shaper can work against Gnutella: Bandwidth Shaper Sample - typical of how some colleges use it (click on link) ie: giving priority to net surfing & low priorities to p2p sharing.

So I'm glad you can at least connect & search whilst at college. If you're using XP, then make sure your XP firewall is disabled. Go to the control panel, double click on Windows Firewall, check the disable box.

Do you see a brick wall in front of the blue world icon at the bottom of LW's interface? If yes, then it's a firewall problem. You probably don't have any control over the cable connection device. If you do, then telnet into it & enable UPnP if it supports it. Else forward a port.

Something else you can try is connecting to a higher port. One between 49152 - 65535. A good one to try is 64049. ie: Go to LW's menu bar, Tools>Options>Advanced>Firewalls & change both connection & listening ports. You may need to restart LW for it to take effect.