Well, just did a forum search on this. There is no clear-cut solution to the error, as there is no clear-cut cause. It has been brought on by many things. Corrupt files. Bad installs. Infections. Unsolved mysteries. Wish I could be more specific, but do a forum search yourself on "no more endpoints available from the endpoint mapper", and you will see the confusion.
The 2 simplest things that fixed it (depending on the cause, if any was found) are multiple reboots or a program repair. (start to uninstall Avast! normally but choose repair)