I just downloaded and installed the new Fan Map Pack, and the files are present in the "levels" folder for FH.
I just tried to join a couple of servers, and got the "map not found" error, even though they were running one of the new maps.
I got it. Somehow, there are two seperate "mods" folders in my installation. The map pack installed to the wrong one. Copied 'em to the right directory and no problem.
Glad you made it, have fun ;)