You've got an old version of XML Injector. Delete all XML Injector files you can find, and download the current version from the Scumbumbo website.
Occasionally we run into mod creators who have included XML Injector files in their own mods, which can definitely cause problems. If you get this LE happening again after fixing your own copy of XML Injector, please generate a mods list for me. Instructions are at the end of How to Use Mods and CC. You can use the paperclip in the Reply window to attach the .txt file those instructions produce.