Our GUI installer almost always installs to the correct directory because it gets the steam install directory from your computer's registry. From there it will know where to install the files because once you enter your username it will know it needs to install to STEAMDIR/steamapps/USERNAME/counter-strike source/cstrike.

In very rare cases steam is either inproperly installed or the files are moved from one place to another via copy and paste and not a reinstall. Whatever the case may be, the registry is sometimes giving the wrong path. The result is that the GUI gets installed in the wrong place.

Running this file will ask you to enter the directory where steam is installed. It will then update the registry and you can proceed to install the GUI.