You might have to go & see your school's computer admin. Find out if they've started shaping bandwidth. Here's an example
http://www2.iwu.edu/IT/help/helpdesk/shaper.shtml
Read through the sticky about connection problems, the first part "... check here first" & just make sure you've got your firewall configured ok. Your AVGfree won't be a problem
Maybe, find out if other people at school have got LW connecting & if so, what they've done to get it working