Tente este conselho ( da BeckyG no fórum HTTrack ):
If you log into your WikiSpaces Wiki, on the upper left-hand side of your WikiSpace click Manage Wiki. If you are an "organizer" of your Wiki, you should have an Export option if you scroll down. If you have the Export option, I think you can save the whole Wiki as a ZIP file. However, if you are not an organizer/owner of that Wiki, you can still download the contents by clicking the Web Folders (WebDAV) link. It should show a web address something like this: YourWikiName.wikispaces.com/space/dav and the last two words in that link are very imporant. Using WinHTTrack Website Copier, start a new project. On the Add URL option, paste in your whole WikiSpaces address with /space/dav at the end. Type your WikiSpaces user name in the Login field (NOT your email address associated with the Wiki... only your User Name will work) and type in your WikiSpaces password in the Password field. Click Next and Finish. Your WikiSpaces site should begin downloading. It won't be "pretty" with images, but it will provide all the files and documents (the text content) of the Wiki.
Eu apenas tentei este método eu mesmo. Demorou um momento ou dois, mas funcionou e foi direto.