Alfresco [repo.avm.OrphanReaper] Garbage collector error

I got this error when running Alfresco 2.2 E without a valid license. Adding the .lic-file in tomcat/shared/classes/alfresco/extension/license/ solved the problem. Complete stack-trace:
10:48:43,184 ERROR [repo.avm.OrphanReaper] Garbage collector error
org.alfresco.repo.security.permissions.AccessDeniedException: Access Denied.  The system is currently in read-only mode.
at org.alfresco.repo.transaction.RetryingTransactionHelper.doInTransaction(RetryingTransactionHelper.java:213)
at org.alfresco.repo.transaction.RetryingTransactionHelper.doInTransaction(RetryingTransactionHelper.java:171)
at org.alfresco.repo.avm.OrphanReaper.doBatch(OrphanReaper.java:342)
at org.alfresco.repo.avm.OrphanReaper.execute(OrphanReaper.java:58)
at org.alfresco.repo.avm.OrphanReaperJob.execute(OrphanReaperJob.java:44)
at org.quartz.core.JobRunShell.run(JobRunShell.java:202)
at org.quartz.simpl.SimpleThreadPool$WorkerThread.run(SimpleThreadPool.java:529)