I do not know what that error means and I have not seen it before.
The error that you are seeing is "package or namespace load failed for 'MSstats' in loadNamespace...". There are also some strange characters and it says "caTools".
You might be able to fix things by uninstalling R version 3.5.0 from your computer and installing that again and then installing the MSstats external tool in Skyline again.
They also might be able to help you if you ask this question on the MSstats support board which is here: