Mqueue.in is filling up!

[Kris Zabriskie]

I'm having a weird MailScanner problem.  Sendmail will sit there and start
tossing mail into the queue.in, not a problem with that.  However when I
look in the mail.log this is what I see:

Jul 29 10:06:03 mustang MailScanner[238072]: MailScanner E-Mail Virus
Scanner version 4.20-3 starting...
Jul 29 10:06:05 mustang MailScanner[244953]: Using locktype = flock
Jul 29 10:06:08 mustang MailScanner[245441]: New Batch: Found 1634 messages
waiting
Jul 29 10:06:08 mustang MailScanner[245441]: New Batch: Scanning 100
messages, 2816396 bytes
Jul 29 10:06:08 mustang MailScanner[245441]: Spam Checks: Starting

However, the messages are not getting delivers, so the queue.in is just
piling up!  Does anyone have any suggestions?