Agent installation errors on Ubunutu 18

I’m trying to install any current agent on an Ubuntu 18.04 laptop and I get a message about needing libc6 v2.0.105 or greater as a prerequisite. I checked my installation and it’s 2.2.X, so it’s much higher, but still not valid.

I also tried running the bash script at https://github.com/jgstew/tools/blob/master/bash/install_bigfix.sh
but I get an error indicating BESAgent.deb.is not a Debian format archive, exit status 2.