It seems to me that when someone uses (misuses?) Bamboo with LDAP as a user repository the AuditLog feature doesn't play with Hibernate well. One cannot enable/disable plan in such situation (he has to disable audit logs). Hibernate is complaing about finding shared references to a collection of AbstractChain.allStages. It seems like AuditLog interceptor is malfunctioning - logs have:

2012-05-15 18:12:29,874 WARN [qtp1022165816-12] [HibernateObjectsAuditInterceptor] Audit Log Interceptor has been called inside itself. This may be indicative of bigger problems...

Steps to reproduce:

1) grab attached export_work.zip
2) start a fresh bamboo 4.0.1 (i.e. remove previous bamboo-homes/8085 folder)
2.1) use 'custom installation' method,
2.2) use default values till last step, where:
3) choose "import existing data" -> export_work.zip
4) bamboo will complain something about import failed - ignore that. Restart Bamboo after finishing importing.
5) login as "admin/admin"
6) go to "test" plan summary page, actions->enable plan
7a) "test" plan is expected to become enabled, instead we observe:
7b) Internal server error:

Stack Trace: 
org.springframework.orm.hibernate.HibernateSystemException: Found shared references to a collection: com.atlassian.bamboo.plan.AbstractChain.allStages; nested exception is net.sf.hibernate.HibernateException: Found shared references to a collection: com.atlassian.bamboo.plan.AbstractChain.allStages
Caused by: net.sf.hibernate.HibernateException: Found shared references to a collection: com.atlassian.bamboo.plan.AbstractChain.allStages
	at net.sf.hibernate.impl.SessionImpl.updateReachableCollection(SessionImpl.java:2905)
(...)