Hi,

I do not use Kmail, but a short search on the SuSE lists (at 
"http://www.geocrawler.com/lists/3/Suse-Linux/") show there are 
tons of problems.

Some seem to have symptoms like described by the original poster. 

So: are you using Kmails SMTP (that sometimes is buggy) or 
another (like sendmail)? Can you send longer messages with other 
programs?

mike