Getting kicked from official games

[stateofmisery]

I'm getting thise when I try to join or am invited to join L4D 1:steam server is enforcing consistency for this file scripts/instructor_lessons.txt, I'm not sure what it means, but I just had some kind of update to L4D 1 today ( 4/7/2013 ), then when I tried joining games I kept getting kicked with this, I thought it had to do with having the instructor turned on so when I went and checked it, it was turned off. So, I turned it on, left L4D 1 and restarted, then when I tried to join another game I got kicked again for same reason above, so I checked the instructor, IT WAS TURNED OFF AGAIN, so I turned it back on and tried to join a game and got kicked again for the above, sent a complaint to steam, but nothing back, and I've noticed that I'm having a lot of problems with steam, servers, ping, lag and teleporting inside games before this, and freezing. I'm running a Dell XPS 8300, Windows 7 Home Premium, Intel Core i7-2600 CPU @ 3.40 GHz, 16 GB Ram, 64-bit operating system, any help appriciated, I only use this computer for gaming

[Ŧђɇ ƼϮϞ §μȑ√iⱴ۞ѓ]

Whenever you get a message saying :

server is enforcing consistency for this file:

it means your file has differences from the server you are trying to connect to. In your case it's the instructor_lessons.txt file. Try deleting it and update your game again. After that try joining the sever you were trying to connect to.