Db2 referential integrity problem

The situation is quite serious, we have a table in DB2 on AS400 that has defined a foreign key for another table, so we enter a record that has a regular ID of the referenced table, so when we enter the SQL insert through the front end tool everything went fine ,

The problem comes when this insert has to be done through a java application that uses Spring Framework (SQL handler only, web services ...), so everything ends up with PreparedStatement using jdbc drivers in jt400.jar. We received a "referential integrity check failed" message, which we checked was not possible.

Does it have any similar similarities? Should we update the JTOPEN library? Now there is a real version 6.5, we are using 6.3 in production and are afraid of the negative consequences of upgrading to 6.5.

Forgot to mention, restarting Tomcat (application server) has no effect, but if I restart the linux box (ubuntu 8.10) everything is fine. The connection to the database is done by JNDI.