Download this autoexec.cfg config and put it in:

[Game folder]/cstrike/cfg/

Then open this config with nopetad or any other text editor that you use and replace 'your password here' with the password you got.

 

Simple example:
My password - 123456789

setinfo "NiDEAdminSecure" "123456789"

 

Or if you have already used autoexec.cfg with your settings, then just add to the end of the file follow line:

setinfo "NiDEAdminSecure" "your password here"

and replace 'your password here' with the password you got.

 

 

Restart your game after autoexec.cfg done, join the server & enjoy.