Fail to download from Stanza desktop

Hi,
I'm trying to share books from Stanza Desktop to my iphone, which I've never had problems with before. However, this time I keep getting an error message:

Failed to download and import: Unable to translate for import: Unable to parse OPF data from zip/private/var/mobile/Applications/939EAB96-5867-4D63-965F-9E3C4ACE09FD/tmp/Downloads/download-0.translate

Can anybody help?

thanks