Hi there! Last week I updated to Avira Security Suite v9 and this key was stored in the registry (XP and VISTA tested):
HKCR\{80b8c23c-16e0-4cd8-bbc3-cecec9a78b79}
It has no data under it, so that's why CCleaner tries to clean it (I think). Maybe you could provide a "Ignore selected entries from now on" button.
Thanks!