[imp] Submitting new msg to send, zero size reply

[agullo at comtenidos.com]

Hi,

Still testing latest stable Horde & Imp releases to update my current 
setup. Getting problems to send messages with attached files.

With Imp 3.1 in production, max php upload size in php settings 
currently limited to 2mb. If I try to send a msg with an attach aprox 
larger than 400-500kb, uploading is ok, but when I click on 'send', 
something is executed, tmp attached file is unlinked from tmp directoty, 
but message is not actually sent. Popup compose window still open, I 
click again on 'send', msg is actually sent this time, but no attached 
stuff at all (if I check the resulting message source, 
attachment-related MIME labels are there but no real content at all.

With testing Imp 3.2.1, same problem, small attachments are ok, but 
anything larger than a few hundred kb is refused with a null output 
reply from the webserver. If browsing Imp thru a Squid cache, I can see 
a "Zero Sized Reply" error from the cache engine. Uploading is fine, php 
upload limits are not enforced for these small attachments.

Logging at debug level is not enough, I don't get any feedback from 
logs. What else should I look at?

Thnx