Anthologize is a free, open-source, WordPress-based platform for publishing. Grab posts from your WordPress blog, pull in feeds from external sites, or create new content directly in Anthologize. Then outline, order, and edit your work, crafting it into a coherent volume for export in several formats, including PDF, EPUB, and TEI.
I can confirm the problem comes from Wordpress on Windows. C: and confusion between the forward and backslash in path substitutions... More a wordpress problem but if you could find a patch would be great...
I can download the ePub but it seems empty and Sigil gives me the following error:
Cannot extract file: C:\wamp\www\wp/wp-content/uploads\anthologize-temp\d9cae6cb4e4befe4fbbf6cc03b8b8ccacd520462\epub\META-INF\container.xml