[Dovecot] master request not found

[Marshal Newrock]

I am setting up dovecot 1.0-rc15 as a proxy.  When I try to log in, I
get errors such as the following:

Dec  4 17:39:23 vega dovecot: Dovecot v1.0.rc15 starting up
Dec  4 17:39:24 vega dovecot: auth-worker(default): mysql: Connected to
localhost (ad_mail) Dec  4 17:39:31 vega dovecot: auth(default): client
in: AUTH    1       PLAINservice=POP3       lip=xx.xx.xx.xx
rip=xx.xx.xx.xx       resp=<hidden> Dec  4 17:39:31 vega dovecot:
auth(default): client out: CONT   1 Dec  4 17:39:31 vega dovecot:
auth(default): client in: CONT<hidden> Dec  4 17:39:31 vega dovecot:
auth-worker(default): sql(XXXX,xx.xx.xx.xx:
query: SELECT NULL AS password, host, destuser, 'Y' AS proxy FROM
exchange_proxy WHERE user='XXXX' Dec  4 17:39:31
vega dovecot: auth(default): client out: OK     1
user=XXXX    host=XXXX
destuser=newrock.marshal at acd.net        proxy   pass=<hidden> Dec  4
17:39:31 vega dovecot: auth(default): master in: REQUEST 1       171931
Dec  4 17:39:31 vega dovecot: auth(default): Master request 17193.1 not
found Dec  4 17:39:31 vega dovecot: auth(default): master out:
NOTFOUND       1 Dec  4 17:39:31 vega dovecot: pop3-login: Internal
login failure: user=<XXXX>, method=PLAIN,
rip=xx.xx.xx.xx, lip=xx.xx.xx.xx


dovecot.conf contains:
auth default {
  mechanisms = plain login
  passdb sql {
    args = /etc/dovecot/dovecot-sql.conf
  }
  userdb static {
    args = uid=0 gid=0
  }
  user = nobody
}

In dovecot-sql.conf:
password_query = SELECT NULL AS password, host, destuser, 'Y' AS proxy
FROM exchange_proxy WHERE user='%u'

I have verified that I can log into the remote server from the proxy via
pop3.  Unfortunately, there isn't currently imap access to the remote
server.  I am connecting to the proxy using pop3 (with "telnet
localhost 110").

Any suggestions what the problem could be?

-- 
Marshal Newrock, Ideal Solution LLC
http://www.idealso.com