Error: File is not valid XML

When I want to edit my reference styles, it warns me that "Error: File is not valid XML" no matter what style I'm editing.Anybody knows how to fix it?
188BET靠谱吗https://s3.amazonaws.com/zotero.org/images/forums/u11441413/gkz7h0vx29xmm779axj5.png
Sign Inor Registerto comment.