cs.strike.exe fails to start.

[vvvv0101]

When trying to start cstrike.exe, the following message appears:

Fatal Error
Failed to initalize authentication interface. Exiting...

I've already tried it both logged into Steam and outside of Steam, and it didn't work. How can I solve this problem?

Here's the path where I pasted the CS Steam files and the Nextclient files:

C:\Program Files (x86)\Counter Strike 1.6 NextClient\Half-Life

[Polarhigh]

Try placing the folder outside of Program Files (x86) or Program Files. CS cannot function correctly from these folders