Org.hibernate.TransactionException: Transaction not successfully started

Estou recebendo essa tela no navegador:

[code]HTTP Status 500 - org.hibernate.TransactionException: Transaction not successfully started

type Exception report

message org.hibernate.TransactionException: Transaction not successfully started

description The server encountered an internal error that prevented it from fulfilling this request.

exception

javax.servlet.ServletException: org.hibernate.TransactionException: Transaction not successfully started
financeiro.web.filter.ConexaoHibernateFilter.doFilter(ConexaoHibernateFilter.java:50)
root cause

org.hibernate.TransactionException: Transaction not successfully started
org.hibernate.transaction.JDBCTransaction.commit(JDBCTransaction.java:131)
financeiro.web.filter.ConexaoHibernateFilter.doFilter(ConexaoHibernateFilter.java:39)
note The full stack trace of the root cause is available in the Apache Tomcat/6.0.37 logs.[/code]

[color=red]Não estou conseguindo achar esse erro. Alguem já passou pelo mesmo problema?[/color]