Post 5 above contains the basic instructions.

If you bought OmniFocus through the Mac App Store, and are using one of the scripts above which contains the string:

"~/Library/Caches/com.omnigroup.OmniFocus/OmniFocusDatabase2"

then you will need to edit it to:

"~/Library/Caches/com.omnigroup.OmniFocus.MacAppStore/OmniFocusDatabase2"