I've used prior versions of StuffIt, both paid and free versions for over 10 years, probably almost 15, and it has always been a valued utility (I was an IT consultant to medical and dental offices for over 10 years). However, there seem to be occasional problems with installation like the one I encountered today.

After downloading, I tried to install, and the installer gets past a couple of screens including the EULA and Read Me but then it quits suddenly with a dialogue box that says:
"Missing Critical Component
Installer help application missing."

Since I'm updating a lot of my software during lunch, I have managed to do a number of update installs thus far, and therefore have no reason to believe that it's my machine...

Unfortunately, I don't have time to diagnose the trouble at this point, so I'll wait for them to "fix" the installer.