error C2504: base class undefined

Hey, I've been playing with the Source SDK (Half-Life 2 Code), and got this error. I have included all the correct files, so i don't know why it cannot find the CHL2MPRules baseclass... :S

build_gamerules.cpp
d:\modding\hl2\boamod\src\game_shared\hl2mp\build gamerules\build_gamerules.h(40) : error C2504: 'CHL2MPGameRulesProxy' : base class undefined
d:\modding\hl2\boamod\src\game_shared\hl2mp\build gamerules\build_gamerules.h(47) : error C2504: 'CHL2MPRules' : base class undefined

Files can be found here: http://www.leightosoft.com/code/ Cheers Marine