If you are using your spell book to click on DE icon, I suggest you move it to one of the Bartender Bars. I've had a similar problem when I've tried to replace glyph's and it brings up the same message. Reloading UI or logging in and out works as a short term measure until the person/persons who wrote the add-on update it.
So just to clarify, Drag the DE Icon from the Spellbook and place it on one of your Bartender Bars
What Taryble said - when you're using embedded libraries (the default) and any library causes an issue - the first addon to load it will be blamed for it.