I am running Linux Mint 20.1 and have attempted to download QCAD/CAM trial version 3.31.2 and have also tried the QCAD pro trial download. In both cases I get an error message complaining of invalid characters and (even disregarding this) cannot proceed further, please see screenshot. Please also assume a high level of ignorance, so simple instructions would be appreciated.
Your system is trying to open the installer with a text editor application. This will not work.
Please refer to our installation instructions at:
In short, you need to make the downloaded file executable and then run it.