Error: "ProcName value not found on command line or in rev.ini.Please edit the file." Help!

Editing the file must be done using a special notepad. In the folder with the game Counter Strike Source, drag the file rev.ini to Notepad2.exe. Make any necessary edits and save your changes.
The notepad itself is already in the folder with the game Counter Strike Source

If you only need to change the nickname, then the easiest thing to do is not edit the file, but use the “setname” command in the game itself. More details are described here: How to change the nickname in CSSIf the error is not resolved (unlikely):
Check for the presence of the line:
ProcName=hl2.exe -game cstrike -steam -silent -lv /help -novid
add it if it is missing.

When installing the game, the file is already configured correctly, make sure that your game folder does not contain Russian letters. Use folder names only in the Latin (English) alphabet.

You can also simply download and save the rev file (rev.ini) with replacement to the root of the game folder.
Original file:
rev.ini