[imp] Strange Attachment problem

[fabricio bianco abreu]

Hi folks, 
 
I have experienced a very strange attachment problem. 
 
I have composed a message that had no text and a small MS-PowerPoint 
presentation (a 100k file) attached and send it to, say, three users the 
message is received and the 100k file is presented as an attachment. 
 
But if I send the very same message to a larger number of addressees, i.e. 50 
users, the message is received and the 100k file is embedded to the text area. 
 
What could possibly have gone wrong? 
 
I am using IMP 3.1, Horde 2.1, Apache 1.3.26, Php 4.1.1, Imap200c server. 
 
Any hints, 
 
Best Regards, 
--  
Fabricio Bianco Abreu  
Tribunal de Contas do DF  
Telefone/Phone +55-61-314-2236