I have a map that builds fine but when I run it in-game and enter buildcubemaps into the console Source CTDs with the Engine Error "LoadBSPFile: odd size for lump 56". Checking the map for problems in Hammer comes up with nothing that could conceivably be causing this. (A few "Entity (func_breakable_surf) has unused keyvalue "error"" and one "There is no player start.")
The map is for Hidden 4b. Here's a link to the VMF: https://dl.dropboxusercontent.com/u/101 ... n_wip7.zip