Do you have any other computers on that router wi-fi or wired? How are they configured for networking?
It is possible to configure IP, subnetmask, DNS and gateway manually on the Blackberry but normally we want to avoid this and let DHCP look after that for us.
If you edit your profile on the Blackberry there is a checkbox "Automatically obtain IP address and DNS" which controls whether the BB uses DHCP (checked) or you enter the values manually (unchecked). What is the state of that checkbox?
My other Blackberry is a PlayBook.