The GUI crashes whenever you try to add an attachment. You may also have noticed that the GUI doesn't crash if you use the installer.
You're most likely using the portable version and have chosen to omit certain files from the archive, or you're using older versions with a newer .exe. You must not do that. All programs from version X require their auxiliary files to be present and to be from the same version.
Note that "portable" does not mean that you can take the .exe files and nothing else and just use them.
It means that you can take the whole installation including all of its files and put them anywhere and run them from there. It also means that the programs won't store their settings in the Windows registry; instead they use configuration files located in the same directory the .exe files are located in. Think of putting the application on a USB thumb drive and carrying it around with you.
Keep all the files from the portable archive. Never mix files of different versions.