That would indeed be bitter to find out, considering how much time I invested in discussing the archive preview feature with the developers and submitting bug reports of it (I'm the person who suggested a way to implement RAR archive preview, among other things).
Mass Downloader is discontinued and thus we neither develop nor support it any more.
Thank you for your support, and please feel free to contact me with further questions. I will gladly assist you.
Elena Klimova | MetaProducts Systems® | email@example.com | www.metaproducts.com