Thanks, all.

It's a company computer, so I can't disable the security software. Until recently, we weren't able to install anything ourselves. A couple of months ago, IT installed a utility that allows us install with elevated privileges. I've installed a couple of other things fine, but I wonder if the issue could be with this installer utility. Our in-house accessibility team suggested I try installing a portable copy on a USB drive, so that's probably my next step.