Invalid CHAR in quoted string...

[Romans]

Hello.

I have been watching internet discussion boards for over a month for the 
solution of this problem, but nothing useful seems to came up.

The problem is that sometimes users (only IE users, but it's not 100%) get the 
following error (1-2 of them):

Warning: Invalid CHAR in quoted string: ed (errflg=1) in Unknown on line 0
Warning: Invalid CHAR in quoted string: ee (errflg=1) in Unknown on line 0
Warning: Invalid CHAR in quoted string: 92 (errflg=1) in Unknown on line 0

This is not related with badly-encoded from/to/subject strings. User reported 
(ive got about 20 of those reports) that errors apears in every php file one 
time per session (mailbox.php, prefs.php, logout, ) and everytime refresh 
helps. 

I have disabled php errors globaly but i have got 2 more reports since that. 
:( 
I would solve this problem myself, but i couldn't catch those error messages 
in action. Anyone could tell, where to start digging?

I'll send configuration files on request;


great thanks,
romans,
www.mail.lv

p.s. Thankyou for the greatest PHP mailing system! Esp. for clean code.;)