Looking at the error message again, I don't think the issue is within the scripts mentioned. From the looks of it, they're all trying to call up that apparently undefined method in some way or another. We need to find where it's at, because that's the issue.
However, as far as I know, it could be almost anywhere in the scripts. At this point, importing everything to a clean version of Essentials would probably be much less tedious than the alternative: replacing each section of script until you find out which was causing the problem.