"Filesystem.ddl is missing" Please Help

When I try to start the game, an error message comes up saying, "The program can't start because Filesystem.ddl is missing from your computer. Try reinstalling the program to fix this problem." Should I do what the error message tells me, or is there another way to go about this? Many thanks.

Go to Steam->Library->Company of Heroes (New Steam Version)->Local Files->Verify integrity of game cache. Wait until it finishes and it will download whatever is missing.

If you are using a different Steam version of CoH rather than that one, just replace it with the one you are using; if you aren't using the Steam version at all, I'm afraid I can't offer any assistance.