I've used this module without incident on several sites and the only one I've had trouble with is a site with an umlaut in the site name.

The backup seems to work (it created a 200MB file) and it downloaded fine but when I open it with 7-zip and try to extract it I get a archive corrupted message. The umlaut in the filename appears as random characters.

Do you think that's the problem? If it is, do you think this module can be made to use the transliteration module when creating the archive?