I can open up hammer fine but here is the main problem. I click file then open and click on a map. Then as soon as I do that it says "Failed to load some default scheme file. The map views may be missing some visual elements." then I click ok then it says "reading chunks" then It stops and I get an error and the next error says this "Model models/props_lights/lamp001.mdl not found and models/error.mdl couldn't be loaded." please help is there anyway I can fix this???