Try this:
On your BB go to:
HTML Code:
http://mobile.blackberry.com
Click on the link that says "UMA doesn't work on my device...etc." and follow the instructions there. Then reboot the device by removing the battery. If it still doesn't connect to UMA then I suggest going to a Starbucks and seeing if it will connect there. If it connects there then it's a router/isp problem. If it doesn't connect there then it's a device/network problem.