I'd like to point out that Steam is prone to create long paths, so if you weren't able to run HR with it, move game's folder to the root of any drive or rename "Sid Meier's Civilization IV Beyond the Sword" to something shorter. You can still use Steam multiplayer if the game isn't in a Steamapps folder, but you shouldn't launch it from Steam or it's shortcut in this case. Maybe having Steamapps in root is enough, I personally nested mine when I tested (X:\Steam Apps\steamapps\common\Sid Meier's Civilization IV Beyond the Sword\).
UPD: on the other hand, maybe that wasn't the reason for me, because mod loaded fine from a moderately deep path when I didn't use Library to run it. Still ruins multiplayer if your checksums (including the base game) don't match.