From the offcial site, should solve your problems...
"Error! Server verification failed" Problem
==============================
This error is caused by the client's inability to communicate with the Secure Master servers to validate the security module being used on secure servers. It can be caused by a few different problems. Here are some things to try:
1) Clients need to communicate with the Secure Master servers (port 27012). First, make sure there isn't a firewall problem.
2) Make sure you do NOT have a file called "woncomm.lst" in your \cstrike folder. If you do, delete it. This file should ONLY reside in your \valve folder.
3) Open the "woncomm.lst" file in your \valve folder (using notepad) and make sure there is an entry that looks like this at the bottom of the file:
Secure
{
half-life.speakeasy-nyc.hlauth.net:27012
half-life.speakeasy-sea.hlauth.net:27012
half-life.speakeasy-chi.hlauth.net:27012
}
4) If your "woncomm.lst" file DOES have the "Secure" entry and you still can't connect to the Secure Master servers, it might be a DNS problem. Try changing your "Secure" entry to look like this:
Secure
{
216.254.95.155:27012
64.81.178.5:27012
64.81.159.155:27012
}
"TrackerUI.dll invalid" Problem
======================
This error is harmless and doesn't mean anything. To remove the error from your console, simply follow the same steps outlined for F1 and F2 binding problems (below).
F1 and F2 Binding Problem
===================
To be able to bind your F1 and F2 keys: Go to your Half-Life (or Counter-Strike Retail) directory, open the "valve" folder, open the "cl_dlls" folder, and rename the file "GameUI.dll" to something else (i.e. "GameUI.bak"). You should be able to bind your F1 and F2 keys again.
