Index: src/main/java/org/jbpm/persistence/db/DbPersistenceService.java
===================================================================
--- src/main/java/org/jbpm/persistence/db/DbPersistenceService.java	(revision 6768)
+++ src/main/java/org/jbpm/persistence/db/DbPersistenceService.java	(working copy)
@@ -127,7 +127,11 @@
     if (!isTransactionRollbackOnly()) {
       Exception commitException = commit();
       if (commitException != null) {
-        rollback();
+        try {
+          rollback();
+        } catch (Exception e) {
+          log.warn("rollback failed", e);
+        }
         closeSession();
         closeConnection();
         throw new JbpmPersistenceException("transaction commit failed", commitException);