"Internet not available" error while trying to connect to wifi I have a samsung galaxy chat B5330 device.

Whenever I try to connect it to wifi, I get various errors as follows,


Using DHCP :- Here it shows a "obtaining IP address" message but never connects.
Using Static IP :- It connects to wifi but then shows a "internet not available" error. I'm sure that internet is available as many others use it successfully using other android devices/laptops etc.


EDIT:
I found out that not all are able to use the wifi. Some do not get connected(stuck in "obtaining ip address"), some get the "internet not available" error, some connect and get internet but at very slow speeds(10 KBps download speed) while some lucky dudes get blazing speed(10MBps download speed)

Could this occur due to to many signals at same place? At any given place in campus, we get at least 2 strong and 1/2 weak wifi signals, not to mention some secured portable wifi hotspots from androids.

How do I solve this error.

Note that I don't own the router/wifi, it's open(No security, accessible by any student.)
Seems DHCP is not enabled on WIFI router, you may need to ask others to obtain DNS
address, to connect to internet, DNS info is required as well