BrokenEagle98 said:
What tags were you trying to use? The above error should only occur if an implication relation exists. In other words, there should be an implication
??? -> artist_name
. I can't really say more than that without knowing what post you were trying to change, and what tags you were trying to change.
For instance, in post #2969426, the original uploader tagged the image as rentille, and then I changed that to artist:rentille