I have found other posts about this, but nothing helped me to solve this problem. I don't know if I did it right, but I tried a lot of things...

When I click on Multiplayer the game crashes and the windows tb.exe stoped working...

-The game is up to date. (downloaded the game 3 days ago)
-My firewall is allowing tb.exe and toribash.exe.

-My system conf:
Windows 7 Home Premium 64 Bits
Intel Core i5 2.3GHz
4 Gb RAM
NVIDIA GeForce GT520M

Can anybody help me?

This is a known problem that happens to a handful of Windows 7 users when trying to access multiplayer.
This problem will be fixed when hampa gets his hands on a Windows 7, please be patient.