It's either a software or hardware problem.
Lots of consumer level nic cards are cheap pieces of doo-doo. Not great, but good enough to do what most desktop users need them to do. Namly fetch email, browse the web, instant messaging and the occasional download.
Or it could be a driver issue. Sometimes the manufactures just don't expect to have juggle dozens of connections at once on a desktop computer, so it's not suprising that the thing will keel over and die from the workload.
Try installing the newest drivers you can from your manufacturer's website. If that doesn't help, maybe you can borrow a different PCMCIA nic to try out in your laptop and see if you run into the same problems. That way you can isolate the problem. (your using regular cat5 eithernet, right?)
If it's fixed buy new drivers, then it was a driver issue. If it's fixed buy different hardware, then it was your nic itself. If it's fixed buy neither then it's either your OS (or just both nic cards you tried out suck) or the campus network. If it's working on a different computer just fine, then it's probably not your campus's network.
So this is happening with your Laptop, right? What chipset is it using? Onboard or PCMCIA....