Guys, this may sound like a rant, and it is to a degree :-)
You should deliver the correct versions of shared objects that your installation depends on. Your program wants zlib 1.2.9, but 1.2.7 was installed by the installer. Renaming the file and deleting the links does it.
If you install files with a superuser bit set (PixInsightUpdater), you should inform users before you do so because this is a very serious security issue ! Linux is before all a multiuser OS and such hacks are completely unnecessary, if not smelly.
Anyway, i suggest that you should allow the user to install software where she/he likes, especially in her/his home directory to avoid mingling with vital things like dev environment etc. As it is now, pixinsight must be installed in a vm or on an own pc.
Apart from that, it is the best linux program for the use case on the market.
Just sayin' ...
:-)