I had exactly the same problem with the same registry entry. No amount of running the Registry cleaning part of CCleaner would remove this entry. I also couldn't manually delete it via the Registry either as I was getting a security warning.
I then thought about what programs I had installed recently - the main one was Avira AntiVir Personal and specifically I had chosen an option (or at least I think I chose the option) under Configuration - (tick Expert Mode option) - General - Security to "Protect files and registry entries from manipulation". I unchecked that option and was then able to delete this registry entry and it has stayed deleted, even after I retick that security option.
As the registry entry is no longer there (I did a search through the Registry after re-enabling that security option, saving the configuration and restarting the computer) I don't know if that security option is really enabled any more but it has at least sorted out the entry that CCleaner kept finding and then failing to delete.