Pdp Authentication Failure Iphone 3g

I have an unlocked “Originally on Fido, Now on Rogers” iPhone that has seemed to cease MMS functionality. )=
I originally had another iphone which was stolen. (it was Locked to rogers) and I could use Swirlymmsas I pleased. I then bought the Fido one (mentioned above), jailbroke it, unlocked it, installed SwirlyMMS and was having no complications untill now. When I start swirlymms it will pop up with a message after about 5 – 10 seconds saying “PDP Authentication Failure” or “Failure to Activate Cellular Data Network”. This is really annoying, and any help would be appreciated.
FYI Info: Its a 3G Iphone on Rogers, unlocked with Yellowsn0w.