[Exim] Heavy traffic problems

I had asked this before and tried the suggestions, but I'm still getting the
same problems...maybe there's something else I can do (other than run it
with full debugging, run out of harddrive space, cause a kernel panic, and
destroy the machine).

This machine's primary use is to handle the mailing list for my site...we
send out a little over 700 emails nightly. It used to stream them all at
once, but that caused problems, so now it streams 100 at a time, disconnects
and waits 2 minutes, then streams another 100, etc....Seems to work.

I keep getting these in the logs:
2001-10-01 23:05:28 15jBYm-0008Nd-00 failed to open DB file
/var/spool/exim/db/retry: Permission denied (euid=80 egid=80)

To solve it, I even made the entire directory tree and the file "retry"
itself mode 777...still no luck. The exim binary is set +s...so it can't be
that. To make matters worse, all the files in the 'db' dir are 0 bytes and
the last modification date was June 1st of this year....the day I was
instructed to delete them and let Exim remake them.

It doesn't seem to bounce messages correctly, either. It just sits in queue
and keeps attempting to send it, even past the retry limit. I have it in
split spool directory so I can't see exactly how many messages are still
sitting there...but I looked in a few dirs and each had a handful.

It's getting pretty frustrating, since I've had this problem for over a
year...just haven't found the right solution yet. It's the only
installation of Exim giving me trouble, too...the rest of my installations
work perfect (they're not subjected to such heavy traffic, tho).

Let me know what you need to see in order to think of a solution...I
wouldn't know where to begin pasting configs, error logs, etc since it could
be anything...

-Sam