I'm connected directly to my DormNet modem (a.k.a. the dorm room wall). It was working before break, but I had to unplug it, and now it doesn't work. I'm setting up from an iPad.
I would suggest that you contact your university's IT department for assistance. A number of schools do not allow personal Wi-Fi devices and those that do may require that you register the device's MAC address in order to gain network/Internet access.
The fact that it worked before may indicate that neither of the above is necessary ... and it may only mean that you just need to reset the AirPort to get it working again. This would especially be true if you had repurposed the AirPort during the break.
My AirPort express has a solid green light, but my Internet connection blinks on and off.
