Salut mecs, the problem hints to an inavailable ressource on the session bean, like a delayed of unavailable datasource.You shold check the server.log for any kind of ressource problems. In our case, our web-services suddently ran into the same problem,. throwing the same exception. We are using an Oracle-DB for to persist our data. Sombody changed the OracleDialect to OracleDialect or another one finally we hat the problems with our webservice. Some week later i noticed error messages (only one line) like this one: server.log.2009-10-02:2009-10-02 11:28:36,575 INFO [org.hibernate.dialect.Dialect] Using dialect: org.hibernate.dialect.Oracle10gDialect server.log.2009-10-02:2009-10-02 11:39:37,602 INFO [org.hibernate.dialect.Dialect] Using dialect: org.hibernate.dialect.OracleDialect server.log.2009-10-02:2009-10-02 11:39:37,602 WARN [org.hibernate.dialect.Oracle9Dialect] The Oracle9Dialect dialect has been deprecated; use either Oracle9iDialect or Oracle10gDialect instead Despite the fact, that this are only warnings, i guess, i found that smoking gun. Assumption: The error/warning condition slowed down the session bean, causing the WS unsuccessfully searching for a session bean, that has not been started. I switched to the Oracle10gDialect and the problem disappeared! Voila View the original post : http://www.jboss.org/index.html?module=bb&op=viewtopic&p=4259234#... Reply to the post : http://www.jboss.org/index.html?module=bb&op=posting&mode=reply&a...