It seems you are posting entirely different issues. The first one is a problem we cannot obviously reproduce in any way, but it's a minor issue that doesn't affect in any way the installation, just the logging of the Live Update, and I believe it's already fixed in the current version of the Live Update so, if you run it now, it should download a small update and the error should disappear.
The "problem raised by engine or unspecified addon" SEEMS to be caused by another 3rd party product interfering in some way. Do you use AS16, perhaps ? Another users reported the same error, but said it happens ONLY when starting AS16
The last post doesn't seem to have anything to do with this. Please do not piggyback on post that do not have anything to do with your problem, unless you have EXACTLY the same error, so post an error report as the original poster did. If the error is not exactly the same, post in a new thread, with a proper title, and with a proper error report. "Couatl crash" is NOT an error report.