HaloMods "Classic" Read-only Archive

I don't know if it's a compressed file. I get the message with all user-created files and all the maps that come with Halo CE. The only maps I can open are the original maps for the original Halo.

Follow this link to get the netfx file: http://www.microsoft.com/downloads/resu ... layLang=en

When I try to open a file, it says that it is 'not a valid halo map file', even though it is.