The problem is with Policy manager and NLS. There is a License connection table. When a user logs out, the connection table should be updated. With this problem, the user is not removed from the connection table. When policy manager goes and references that user, it realizes that the connection no longer exists. It issues the C0001001 error, and clears the connection. At this point, the problem is remedied.
One other cause of c0001001 errors on an update is that time is not synchronized. The handle will be added to NDS with the partition time instead of the current time. NLS reads the handle in and thinks the handle is stale and removes it. When the update occurs the handle is gone.