I think you will be able to fix this problem if you install the "Visual C++ Redistributable for Visual Studio 2015" from here:
The Skyline 21.1 installer includes "percolator.exe", but it does not put a couple of other .dll's that percolator needs in the correct place. Those dll's are "msvcp140.dll", "vcomp140.dll", and "vcruntime140.dll".
When you install that Visual C++ Redistributable, those dll's get put in a shared place on the computer where all programs can access them, so it won't matter that Skyline 21.1 did not include them in the right place.
We have fixed this problem in Skyline-Daily, but this workaround is required for Skyline 21.1 if you want Skyline to perform a peptide search.
Lots of other programs that you might have installed on your computer can cause those "xxx140.dll" files to be installed in the shared location on your computer. That would explain why only some of your computers are experiencing this problem.
I am not 100% sure that this will fix your problem, since I think you are the first person to report it, but this problem is very similar to a different problem that we had with Skyline-Daily back in August which makes me think this will be the correct fix for you.