The installer failed to contact our servers to get the encryption key, so it thinks the game isn't out yet. You will need to launch it manually with the parameter:
You can do this with the command line, or by making a shortcut and adding the parameter to the end of what's in the target field. For example:
Download the client zip from one of the links here, and then put the gesource folder in
Steam/steamapps/sourcemods. Note that you can only install Source mods to your main Steam library (under the location which Steam itself is installed).
This indicates that the .dll files for GoldenEye: Source are corrupt or missing. Download and reinstall GoldenEye: Source.
Validate your local files for Source SDK Base 2007. You can either:
Click here to validate through Steam, or validate manually through Steam: