From address not used?

According to the docs, when setting up an email service (I'm using IMAP and NonQuotedCommentHandler), if the address in the 'From:' header is a JIRA user, it'll use that user as the author of the comment. However, it always seems to use admin for me. I presume it knows to strip off the non-address portions of the 'From:' header, right?

I don't know if it matters, but I just noticed this in the logs:

2004-11-12 03:12:47,689 WARN [core.entity.transaction.JNDIFactory] [JNDIFactory.getUserTransaction] Failed to find UserTransaction named java:comp/UserTransaction in JNDI.
2004-11-12 03:12:47,848 WARN [core.entity.transaction.JNDIFactory] NamingException while finding UserTransaction named java:comp/UserTransaction in JNDI.
javax.naming.NamingException: Cannot create resource instance
at org.apache.naming.factory.TransactionFactory.getObjectInstance(TransactionFactory.java:145)
at javax.naming.spi.NamingManager.getObjectInstance(NamingManager.java:301)

Maybe I overlooked something particular with PostgreSQL setup.