Though I do not see what the problem is here, anytime an application starts sending to the list, you need to evaluate the anti-spam and perhaps more importantly the anti-loop detection for the list.  E.g., a "batch program" that would send the same message to the list, would end up with "duplicate" errors.  We had to modify (at some risk) the loop-check

http://www.lsoft.com/manuals/1.8e/owner/owner.html#kLoopcheck


While you're at it, do a 

SERVE appl_sender_address


Just a tho't.

/Pete