My first thought is that the key is too big to import, or it's malformed somehow and causing the crash. Would you mind PMing it to me so I can take a look at it? Alternatively, you could try importing without the GUI. Open a command prompt and go to the folder where you extracted GPG4USB. There should be a subfolder called bin. In that subfolder will be a program called gpg.exe. That's the actual gpg program. Save the key in that folder, in a text file called whatever.asc. Then at the command prompt, while you're in that folder, type:  gpg.exe --import whatever.asc It'll either import properly or if it fails, it should print an error message. Copy the error message and paste it here.