stachu30

Miałem podobny problem na Windows 7 i udało mi się go rozwiązać dzięki pomocy od Steam`a:

If you are running in Windows Vista or Windows 7, please completely exit Steam, and right-click on the shortcut which you use to launch Steam and select "Run as Administrator."

If you are running in Windows XP, take the following steps:

1) Exit Steam.
2) Go to the "Start" menu, select "Run", type "regedit" and click "OK".
3) Navigate to the following registry key: HKEY_CURRENT_USER\SOFTWARE\VALVE
4) Right click and select "Permissions"
5) Check the "Allow" boxes for "Admin" and "System" for both "Full control" and "Read".

The remaining steps apply to *all* versions of Windows.

Then, verify the game's files at least once:

Title: Verifying Game Cache Files (GCF)
Link: http://support.steampowered.com/kb_article.php?ref=2037-QEUH-3335

NOTE: There may be files that fail to validate. This is normal and can be ignored.