some news, it was caused by a recent update of bitdefender 10.

just tried the new test.cgi too. no change

Indeed the test doesn't work on my computer at home. I'll make some tests tonight, the only different thing on my two computers is my Firewall (Bitdefender 10 at home, Bitdefender 9 at work)

By the way the Ajax version works on both.

That's really odd I tried Opera, Firefox 2.0.0.3, IE7 at home (XP pro) I had always the same problem. I just tried at work (XP pro, Same provider, IE7, FF2.0.0.3) it works perfectly.

actually if you upload a big file you'll see nothing but that during the transfer :

Well, I'am trying to install xupload 2.4 on my new server, the upload works but not the progress bar (or the speed meter etc..)

I have the module Perl "File::Temp" installed on the server... could it be the problem ?