Probleme ODKAggregate-PostgreSQL

i am using PostgreSql server 9.3 and tomcat 6 when i deploy ODKAggregate on tomcat sever i have error .catalina.out::: the web application [/ODKAggregate] registered the JDBC driver [org.postgresql.Driver] but failed to unregister it when the application was stopped to prevent a memory leak the JDBC has been forcibly unregistered... What can i do to solve the problem?