[TYPO3] problem with directmail getting stuck

[David Lanier]

Hello,

I've encountered an unusual problem in sending emails using directmail.

I have a list that has about 2000 recipeints.  The mailer runs fine (via cron)
and then stops about 200 shy of the end, and never completes.  It has done this
three times now.  When it gets stuck like this, it will not send any new
newsletters that I wish to send.

The only way I have found to get it unstuck is to edit the database record and
manually enter a timestamp in the "scheduled_end" field.

I have located the last email address that was sent to, and looked at the
following email addresses in line.  They all look fine, valid email addresses.

I do get emails from the cron script (every minute) and there are no errors in
it.  (I've even tried removing the -q flag from php, and making sure I get all
the response text from the cron job.)

Manually invoking the mailer engine says it's sending the next 25 mails, but the
mails are not actually sent, and the # sent is not incremented.

My Setup:
Typo3 4.0.4
direct-mail 2.2.0
php 5.1.4

Any ideas on what I should check?  What would make it stop partway through the
list, and not generate errors and not complete?

Thanks for any advice you might be able to provide.

David Lanier