I am running a jailbroken 4.0 on my 3gs (old bootrom) with sn0wbreeze 1.6.2

I've it unlocked it too using ultrasn0w. I downloaded few apps today from apple store. Till morning, it was able to connect to my university campus wifi correctly...but, now it is not even able to connect to it.

As i said, till morning it was working fine, and even my laptop can connect to that same wifi...but, somehow my iphone is not able too

I tried "reset network settings", restarting my phone, restarting the wifi...but, same problem !

Any suggestion ?