That's been a common error. I recieved this from the store I ordered the game:
Vivendi Universal Games has announced two important updates regarding the product installation for Half-Life 2.
1. Half-Life 2 CD Installation error when Counter-strike: Source is not selected
The following has been identified as a known issue with Half-Life 2 Standard Edition (not Collector's or European DVD editions):
Problem: If during the initial installation process the option to install "Counter-Strike: Source" is NOT selected, an error may occur during installation. The message will be: cabinet file error, fatal disk error, or something similar.
Solution: Cancel the current installation process and reinstall the game from the beginning, starting with Disk #1. Make certain to select the option to install both Half-Life 2 and Counter-Strike: Source.
Note: If you prefer not to retain the Counter-Strike: Source program on your system AFTER INSTALLATION, you can
remove it using the following procedure:
* After Half-Life 2 has been successfully installed, open up the Steam client.
* Select the Play Games list
* RIGHT click on Counter-Strike: Source and select Properties
* Select "Delete Local Content."
2. Product Authentication Delay When Installing Half-Life 2
Some consumers may experience delays in authenticating Half-Life 2 during the installation process. This is due to the high volume of consumers who have purchased Half-Life 2 and are installing the game, which is causing high traffic on the Steam authentication servers. Please keep trying, as this is a temporary delay.
Hope this helps.