A couple of things off the top of my head: make sure your brushes aren't tied to any sort of entities or that you have more than one sky_camera.
I don't have any sky_cameras and the objects aren't tied to any entities.
I probably should have included this already, but I do get these lines when I compile:
Valve Software - vbsp.exe (Dec 11 2006)
2 threads
materialPath: c:\program files\valve\steam\steamapps\orangeboxez\counter-strike source\cstrike\materials
Loading C:\Program Files\Valve\Steam\SteamApps\orangeboxez\sourcesdk_content\cstrike\mapsrc\gg_houseraid_a1.vmf
Can't find surfaceprop concrete for material ORANGE_DEV/DEV_MEASUREGEN_GREY07, using default
Can't find surfaceprop concrete for material ORANGE_DEV/DEV_MEASUREGEN_ORANGE01, using default
material "dev/dev_measuregeneric01b" not found
Material not found!: DEV/DEV_MEASUREGENERIC01B
Can't find surfaceprop concrete for material ORANGE_DEV/DEV_MEASUREGEN_ORANGE03, using default
Can't find surfaceprop concrete for material ORANGE_DEV/DEV_MEASUREGEN_REDORANGE01, using default
Can't find surfaceprop concrete for material ORANGE_DEV/DEV_MEASUREGEN_GREEN02, using default
material "tools/toolsplayerclip" not found
Material not found!: TOOLS/TOOLSPLAYERCLIP
Can't find surfaceprop concrete for material ORANGE_DEV/DEV_MEASUREGEN_GREY08, using default
Can't find surfaceprop concrete for material ORANGE_DEV/DEV_MEASUREGEN_ORANGE02, using default
material "tools/toolsskybox" not found
Material not found!: TOOLS/TOOLSSKYBOX
fixing up env_cubemap materials on brush sides...