I have a similar problem (9.0.2.1621). At the beginning querying a table with XMLType columns broke the connection with ORA-3137. This happened for 11.1.0.6, 11.1.0.7 and 11.2.0.1 clients. Fortunately 11.2.0.2 fixed it. However only the first query works now. The next query in the same session...