Yes, this error can be caused by a partially updated system.
However, the more likely cause is that you are using customised .xml files. A lot of these have changed in the recent update. For example, the skill window now has the char editation buton out of the box. The custom version I did does no longer work, and since it serves no purpose anymore, won\'t see an update from me.
So basically, remove the readonly attribute from all custom files and let the updater overwrite them with the curent ones. If you back them up before, you can later redo the ones you need to redo. This is what I did.
