could not active cellular data network you are not subscribed to a celluar data servi

[businesssuit]

I saw an answer to this if you have a MAC by downgrading itunes to 8.2b7 but I am using a WINDOWS XP and I don't see an answer to this.

Unlockit - APN Changer for your iPhone

The above website was referenced but when to this website on my iphone 3G in wi-fi mode I can't download any of the files; the phone says it is not supported.

Can anyone give me any advice on how to correct this I am using ATT.

Thank You

[roudaj]

I was having the same problem until I upgraded to 3.0 then the profile would install properly. However, I still get the could not connect error with the new APN Profile installed. I'm with AT&T and have a Blackberry dataplan (its for/from work). I switch my sim back in forth between my BB and my iphone. the data plan works fine in the BB but not the iPhone. Any suggestions? The iphone is unlocked and worked fine until I upgraded to 3.0. I downgraded back to 2.2 but the data still doesn't work. Any help would be greatly appreciated.