I too am seeing this problem in 3.2.1. I'm not sure if it's the same one but it sounds too familiar. Have you found a solution yet?
We had this problem with 3.2.1 (with a LocalTx Datasource). Most of the problem turned out to be our application doing something dumb :) but there also appears to be a bug in the connection pooling.
I'm afraid I never raised a bug report because the problem largely went away when we changed our application.
I've seen exactly the same exception sequence you mentioned in the archive message.
the problem appears when we keep stop/start the datastore and *intentionally* cause the connection to fail to see if the connection pool can recover.
We are forced to work around this problem by restarting JBoss once we detected this exception... No Managed Connection Available!