Go to Your ...\cstrike directory and look for the file config.cfg. Open it by notepad and try to find if there is the line:
bind "`" "console 1;toggleconsole"
If no - add it. Make sure also if there is the line:
console "1"
If there isn't this line add it or if there is:
console "0"
change this "0" to "1".
Let me know if You have been reading this:
http://forums.bots-united.com/showthread.php?t=2576