When installing the patch, you may get an error about a file not being found. What's happening is that the patch is using the registry to try and locate the place where you installed your copy of Homeworld2. If you've moved your Homeworld 2 installation to another folder, or moved files around in that folder, you may have problems with the patch.
Also, if you try to install the english patch on a non-english version, you may see this error. Same or similar if you have a no-cd crack or pirated version installed.
Re-install the game, or put the correct path(s) into the registry under the HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\Homeworld2\ section.
For help or discussion, post here.