[imp] HELP: Server Error w/ Many "To:" addresses!

[lee at disinfo.com]

Hey All,
We're running horde 2.2.4 w/ IMP 3.2.2. Unfortunately whenever someone tries to
read a message in IMP that has a lot of addresses in the To: field (200 - 300
in the messages ive seen), the browser (same error across browsers and
platforms) returns the following error:

"Can not open page.... bad server response". 

Apache's error logs show:

[Fri Jan 30 20:26:43 2004] [error] PHP Notice:  Undefined index: 
session_timeout in lib/Horde.php on line 916
[Fri Jan 30 20:26:43 2004] [error] PHP Notice:  Undefined index:  cache_limiter
in lib/Horde.php on line 918


Does anyone have any idea whats going on here? 

Thanks,
Lee