I have a user who got a new AT&T aircard recently. He's on XP Pro and has no issues using AnyConnect via wired or wireless connections but as soon as he connects with the AirCard, he is unable to establish a VPN connection. Since he's prompted for auth credentials, this error appears to be after he succesfully connects and the tunnel is trying to create.
I've seen several postings in the board regarding the "unable to establish a connection" error but no definitive answers.
Dealign with AnyConnect 2.4.1012 and ASA 8.21