It's a problem with using the wrong setup for Steam, not with the mod/game.
You can search the forums for the problem, you know. Just to let you know, this problem has been brought up many times. There's even a tutorial here at
http://www.twhl.co.za/tutorial.php?id=86 .
To fix: I think the problem happens because you ran hl.exe. Maybe using Steam.exe with -applaunch 70 -mod ts works. If you don't get that, then just don't use Hammer to run your map. Just open up the game and run the map yourself.