lost input channel

From: DM (noemail.please_at_replytogroup.net)
Date: 05/11/04 

Date: Tue, 11 May 2004 08:50:11 -0400

I'm running RH 7.3 2.4.18 on an intel box. Serving mail to about 250
users via pop3 and (mostly) imap. Also using squirrelmail.

I'm getting these messages in my maillog:

i4742FV27851: lost input channel from myservername.com [127.0.0.1] to
MTA after rcpt

I get a LOT of them every day, and its been going on for some time.
Should've dealt with it sooner, but ---- anyway, I've googled it, and
many have asked the same question, but none seem to get a good answer.

What exaclty does "lost input channel" mean, and what are its possible
causes?

Thanks - D