Emails not consistently being delivered to lists

Hello.

Some emails to some lists are not being delivered. 

If a sent message is successful, all list members receive it as does the 
archive
If a sent message isn't successful, no list members receive it, however, 
the list archive receives a copy.

This appears to be happening with all of our lists.  There is no pattern 
to the problem - and we cannot duplicate it at will.

Back in January 2006, I sent an email to this list in referencing the 
same problem.  After some troubleshooting with a list member's advice 
(changing debug level to 700 & checking mj_resend.debug), it was 
determined that there was a problem adding the item to the GLOBAL 
duplicate ID database.  It was suggested that I move it out of the way.  
At that time, this appeared to resolve the problem

Last week, I again tried this (as a quick & easy fix) and unfortunately, 
it didn't resolve our problem.

I then decided to take the route of changing the debug level & checking 
mj_resend.debug, however, that file hasn't been written to for quite 
sometime.  Here's an ls of it:

-rw-------  1 majordomo  majordomo  51200000 Feb 27 06:45 
/usr/local/lib/majordomo/tmp/mj/mj_resend.debug

Perhaps there is a size limit on that file and we hit it on Feb 27...?   

Any advice would be greatly appreciated!