IIS 6.0 and mime types, why can't IIS find my file?

Lesson learned yesterday,

IIS6 will not server files it cannot determine the mime type for.  IIS6 determines the file type from the .extention of your filename, just like windows identifies a files type.

We No Touch Deploy our windows form application from a web server.  It's always been a W2K web server.  Yesterday we installed the app at a client site who is using 2003 server.  All of the files would deploy from the web server accept one.  When I looked in the IIS Log file I saw a 404 for this one file. 

After list serving this and chatting with David Hill at MS and other folks on the DevelopMentor CLR LISTSERVS, we got it resolved. 

Seems we need to add a mime type for this one file as IIS6 will not server up the file unless it's in it's mime list. 

Good resource for this:

http://support.microsoft.com/default.aspx?scid=kb;en-us;326965