I've seen this message many times on our Cisco 3030 concentrator and have found little about it, even on Cisco's web site. What does it mean? We have a tunnel between a 3030 (rev 4.7.2.E) and an ASA 5505 (7.2(3)) that mysteriously goes down. This msg is showing up in the logs. Don't know if it is related to the problem, just wondering what it means.
I have this problem too.