Me again for furher info. Found where the problem lies.
1. in fact the back end script gets called but is not triggered due to the http request constructions. I can't tell if the request is wrongly built or if my server can't handle such request but it looks like the posted file is in the query string rather than in a separate portion of the request as it should be with posted data. 2. Due to this my server returns a 404 that does not seem to be received by the swf movie which than sits waiting for ever or crashes th browser (firefox 3). I have submitted the server part of the problem the Active4D software developper but I think it might be a bug in the plugin. Hope it helps.