Problem with Firefox and custom 404 error page

[orogeny]

My site, http://www.bsc.edu, uses a custom 404 error page. The site uses ColdFusion 9 and is on a Windows Server 2003 R2 server. The error page works in all circumstances in IE, but only works in Firefox when the user has typed in a URL with a .cfm extension. If there is no file extension or a .htm extension, Firefox displays a generic "problem Loading Page" error. Oddly, if one looks at the source code of the generic error page, it is actually the source code for the custom page...Firefox just doesn't display it.

How can I fix this issue?

Examples:
http://www.bsc.edu/about/index.cfm is the correct URL
http://www.bsc.edu/abou/ fails
http://www.bsc.edu/abou/index.htm fails
http://www.bsc.edu/abou/index.cfm fails, but loads the correct error page

All of these links work as intended in IE7 and 8.

[DanRaisch]

Moving to Web Development.

[orogeny]

Sorry about that...my first time on the forums. I should have looked more closely at the categories.

[DanRaisch]

No problem at all.

[AlfonsoML]

Your error handler is sending a wrong content-type:
Content-Type: application/octet-stream

If you switch it to text/html it will work.

[orogeny]

AlfonsoML,

That did it! Thank you so much for your help.

[orogeny]

If anybody is wondering what caused the issue... when I set up the info for the custom error page in IIS I used a "File" path instead of a "URL" path. This caused the problem with the HTTP header file type.