Until Svante gets back to you here with some more information I suggest you download the latest version (2.1.1494.0) from the website:
Once you’ve downloaded it try following Barry’s suggestion by manually decrypting it. With the latest version this may fix your problem.
If it doesn’t then to load the menu Barry talked about you need to click on File, Options, Debug. I’ve included a screenshot to help you. That should make the Debug menu appear in between File and Help.
If after all that you’re still unable to get your file to work then I’d email support directly here. Please let us know what the outcome is because it’s concerning that an encrypted file can’t be decrypted.