It says: Silverlight ;)
Thank you very much, it works with the Flash component.
It seems I have a second problem: some video files are uploaded correctly, but some are not. The exception " PHP no request files" is thrown when uploading some video files. Other videos with the same extension are accepted and can be uploaded without a problem - independent of the size. Is it possible that these video files are corrupt and a checksum is wrong?
These videos can be viewed without a problem on the local computer.
Max