Error #131 problem with patch 2.4

I just wanted to mention that I had this problem after copying from the patched directory to the other alternate directories last night. I basically overwrote the existing files there. After I found a post somewhere about fragmentation (perhaps wow.exe or something else doesn't like a fragmented file) I deleted my files in the main directory as well as the Data directory, copied them from the working patched directly, and everything worked again.

On a non-completely unrelated note. After you patch WoW, can you delete all the patch exe files and patch directories that it's downloaded? Because those things take up a ton of space!

I used to keep 'em just in case but really unless you foresee needing to reinstall anytime soon, go ahead and delete them for space lol; I've begun doing that the past few patches and haven't had any issues yet