Hi Tony,
While we try to fix this issue with Linux installation packages, have you installed the application manually? I refer to simply unpacking the .tar.gz distribution archive on a sub-directory under your home directory, for example:
/home/<your-user-name>/PixInsight
If you do so, you can run PixInsight through the PixInsight.sh shell script on the bin installation directory (e.g., by double-clicking it from a file browser window):
/home/<your-user-name>/PixInsight/bin/PixInsight.sh
Let me know if it works. If not, we'll work to make it run on your computer.