Okay, then I think the root cause is found !
Is there any possibility to get the newest stable version compiled for 32 bit? Can I do that on my Computer?
To be honest, I never compiled a package on my own from the source code and installed it.
I would be very happy to get a how-to if even possible to do it.
It works now!
As already mentioned, the rootcause for my problem was, that the existing Indi Server and drivers SW for Linux 32 bit is rather old.
So I downloaded the source code of the indi core lib from Git to my Computer and compiled and installed it based on the in instructions given in the intall file.
And what shall I say: The mount now perfectly works with the IEQ45pro driver @ 115200 baud.
PS There is no driver anymore for the GEM45 selectable
Thanks to all of you who supported me in this dark hours of life