I discovered this in the morning. Download the att mywireless app from the app store. Go into you features and switch to a different texting plan. Let that process and then go back and reselect your original plan. Next download the 5.1 carrier update and Observe the glory. I noticed my MMS working directly after all this! Minutes before, it wasn't working at all.
Good luck and let me know if this works for the mass population.
Good luck and let me know if this works for the mass population.