[Dovecot] Signal 11 on deliver

I just installed Postfix, MySQL, and Dovecot. Everything is working great (IMAP, POP, SMTP) except that I can't get incoming mail to deliver properly. Incoming mail logs the following:

Feb 2 13:23:52 mail postfix/qmgr[2187]: CE0D41F0263: from=, size=650, nrcpt=1 (queue active) Feb 2 13:23:52 mail postfix/pipe[3594]: CE0D41F0263: to=, relay=dovecot, delay=0.32, delays=0.3/0/0/0.01, dsn=5.3.0, status=bounced (Command died with signal 11: "/usr/libexec/dovecot/deliver")

Running /usr/libexec/dovecot/deliver -d mhoppes@[redacted]

results in an e-mail being delivered to the recipient.

Any thoughts on what my issue is?