In straightforward English, as much as possible:
If you're talking about the online survey software, it's probably built with a lot of Javascript code.
Javascript is a coding language used to make ordinary webpages do interesting things. It'll make parts light up, or move, or some "behind the scenes" stuff to (hopefully) make the webpage easier to use.
You poke around webpages using software called a browser (like Internet Explorer or Firefox). All modern browsers know Javascript, and it's very very easy for the browser to use.
Your operating system is way different. It's what works between the programs on your computer, and the "brain" (computer chip). Windows will run various programs as you wish - like a browser.
So, if you have a halfway decent computer, and your Windows is running OK, then the browser shouldn't be a problem, and definitely not the Javascript IN the browser.
It sounds like the guy is throwing out big words but he doesn't know the problem.
It also sounds like there's a "bug" somewhere, some bad math, probably in the code that Qualtrics uses to write their webpage. This may or may not be Javascript.
Also, I might mention, the guy probably can't fix the problem, since it's probably specific to Qualtrics. They just need to fix the bug in their code.