are you jailbroken or have you ever jailbroken?
i'm having this problem on Rogers. I have friends on every carrier that are NOT having this problem, jailbroken or not. So its not carrier specific, nor jailbreak specific.
The reason I think I'm having this problem is because of the weird ways I've kept my texts. Or at least that's what I think
I've had an iPhone since the first iPhone in 2007. Before I got the iPhone 4, when I would upgrade the OS of my previous iPhones, I would full restore and then only replace the SMS.db file because that's all I wanted to backup.
Then when I got my iPhone 4, since there was no jailbreak at launch, I applied my pre-iPhone 4 backup to my iPhone 4. This caused my MMS on my iPhone 4 not to work because of permission problems. I have to recursively set the permissions of /var/mobile/library/sms to 777 in order to make MMS work.
I then applied this pre-5.0 iPhone 4 backup to my iPhone 4 at 5.0.
I was thinking that this weird journey of my SMSs may be the problem, but I doubt anyone else has done this as well.
If this problem is happening for people that have NEVER jailbroken, that puts me at ease and lets me blame Apple
btw I'm Basir in the apple thread