problem configuration ? upload de fichiers

Hello,

I have a strange problème on my server.

You can test at :
http://glouglou.dyndns.org/~laurent/testalacon.html

This is a simple html form with a file input field. it's a stupid test
with no fonctionality. The form action is the form (i know it's
stupid) but the problème is the following :
When you post a empty form it's ok, the form appear, but if you fill
the file field apache do not respond. Normaly the file must be charged
in the /tmp and the form must be call again. It's not the case, apache
do no respond. Make the test.

Maybe it's a misconfiguration. I don't no.

PS. exscuse me for my bad english.