The active configuration paths that are used by DW are stored on a per user basis. So in the error you are getting this is not where the actual file is stored, it is instead stored in the users configuration folder.
Did you delete or rename your users configuration folder with DW closed, then remove the extensions and re-install them? You will need to do this part to get past this error. Please post back if you have any additional questions or run into any problems with this.