And some browsers are not standards-compliant, and will ignore that header, so you can pull the trick I did in my making "tar.gz" files on the fly column.
I.e. Might some web servers report a 404 error because the script doesn't technically exist at that location?
For those that haven't looked at this column of Merlyn's, he does a post to /path_to_cgi/scriptname.pl/desired_filename.ext
For anyone else reading this, I recommend looking at Merlyn's site because there are a lot of useful ideas and snippets of code that one can use quite often.