The key path you construct doesn't contain a trailing delimeter so you want to use $sKeyPath.'\\'.$_ for subkeys (like you do) but $sKeyPath.'\\\\'.$_ for values (which you didn't do).

Win32::TieRegistry figures out what you meant most of the time because "subkey/valuename" is only confusing if you have a subkey whose name is "valuename". But for default values you end up with "subkey/" which it interprets as a key path with the expected trailing delimiter when what you wanted is "subkey//".

        - tye, but my users call me "Tie" ;)