[jboss-user] TxConnectionManager issue

Hi, While developing a web application on JBoss, I come to the following issue at one point: 19:02:24,119 WARN [TxConnectionManager] Connection error occured: org.jboss.resource.connectionmanager.TxConnectionManager$TxConnectionEventListener@76bbe4cf[state=NORMAL mc=org.jboss.resource.adapter.jdbc.local.LocalManagedConnection@59d02cf0 handles=2 lastUse=1186592544082 permit=true trackByTx=true mcp=org.jboss.resource.connectionmanager.JBossManagedConnectionPool$OnePool@72366ea0 context=org.jboss.resource.connectionmanager.InternalManagedConnectionPool@539904f4 xaResource=org.jboss.resource.connectionmanager.TxConnectionManager$LocalXAResource@63145a0c txSync=null] and then, no database related stuff works any longer on that page, and I get errors like: java.sql.SQLException: No operations allowed after connection closed. org.jboss.util.NestedSQLException: Could not enlist in transaction on entering meta-aware object!; - nested throwable: (java.lang.IllegalStateException: Can't enlist - already a tx!); - nested throwable: (org.jboss.resource.JBossResourceException: Could not enlist in transaction on entering meta-aware object!; - nested throwable: (java.lang.IllegalStateException: Can't enlist - already a tx!)) It seems like some connection dropped / lost issue. I'm using MySQL as a backend. The DS configuration is fairly simple: <local-tx-datasource> <jndi-name>seeDataSource</jndi-name> <connection-url>jdbc:mysql://localhost:3306/Foo</connection-url> <driver-class>com.mysql.jdbc.Driver</driver-class> <user-name>foo</user-name> <password>bar</password> <exception-sorter-class-name>org.jboss.resource.adapter.jdbc.vendor.MySQLExceptionSorter</exception-sorter-class-name> <metadata> <type-mapping>mySQL</type-mapping> </metadata> </local-tx-datasource> What could be wrong? Akos