A Different Double Notification Problem

[We_Ready]

Ok, I've been using handcent since I got the phone and I know to turn off the regular SMS program so I don't receive the text message twice. Starting yesterday my Handcent ringtone would play halfway through and then the regular notification ringtone would finish up and I would get a notification in the bar that looks like a white postcard along with my handcent icon. If I go to the notifications tab from the X home screen it will show that postcard and say I have an unread message but when I push it it takes me nowhere and I just have to clear it. Extremely annoying because it's not coming from the default SMS program and I can't figure out where it's coming from. Any help would be greatly appreciated.