I've made the changes and tested both the export and import on both the 32 & 64-bit systems using both decimal formats. It does what I expect but that by no means suggests it solves your problem. Try it and let me know.
I just tested export and import and if there is anything different than in the previous version, I am not able to spot it. Exported files, as one would expect, still contain the decimal format set in my system settings and imported files have to be in that format to be read properly. I also tested swapping my systems decimal format and the input/output in Solver64 changed as expected. As a result, all "," in the Touchstone files still have to be replaced with "." after export, so other programs like METAS VNA Data Explorer would read the files, which always expect the English number format.
Apart from that I noticed that the time domain x-autoscaling is on by default again, which is nice. Thanks for that.