A strange issue is when uninstalling Addon Manager and Couatl Engine it says it can't find the files even though I had checked they where in the FSX root folder previously. It does uninstall them though.
That's not strange and, as I've said in the other post:
and don't worry about any missing file messages.
That message it's not error, it's just an confirmation that the file that should removed, were missing already so, no need to re-remove them again so, everything it's ok.