Yes, Internet Explorer has this problem. It thinks it's a zip so it downloads it as a zip. I get round it by putting the script in a separate folder on the server from the html and the rest and then putting in a file called .htaccess saying:
code:
ForceType application/x-plsc
That should work.
Adding the type elsewhere didn't work right for me, so I had to use ForceType and a separate folder.