Saw this post, it's older and I am not an IT expert, but this error plagued one or two of my machines this past summer. Thought it was connected with the radio. Worked around by downgrading the AT&T client. That radio, an older pc card model, broke after that - unconnected ! - and I have not upgraded to the newer AT&T client either, so the problem has not resurfaced. "Too fancy" is often the culprit, likely.
*I am an AT&T employee, and the postings on this site are my own and don't necessarily represent AT&T's position, strategies or opinions.