[Zope] file-upload problem

Hi, I'm uploading a file from a form. However, I want the id to be something I filled in the form, namely movie_id. But if I do: <dtml-call "images.manage_addFile(id='<dtml-var movie_id>', file='<dtml-call movie_file>')"> and try to upload it, I get following error message: The id "" contains characters illegal in URLs. If I fill in any name in the id='...', it works as a charm... How do I use a variable in the id field? Maarten Demont maarten.demont@cronos.be