Added some console programs to System PATH, Can't invoke them via the registry

The registry command is not run through CMD and therefore is missing many features, and especially the environment variables that CMD creates from the registry, most importantly the PATH variable.

You could replace the registry command by cmd /c RunHiddenConsole..., but that would sort of defeat the purpose of using RunHiddenConsole.

Another possibility is copying RunHiddenConsole to C:\Windows\System32, which is always searched, although modifying this very important Windows folder should not be done unless absolutely necessary.

Your best solution is really to specify the whole path to the RunHiddenConsole program, as the PATH is not very useful in this case.