All previous versions are available on the Developers tab of the plugin page of the repository => http://wordpress.org/extend/plugins/wp-publication-archive/developers/
But until we know why things are breaking, your system won't really be fixed. Do you have access to server error logs? How is your server set up in the first place? I haven't seen this kind of 404 error ever with the plugin, so I'm concerned.
However, the next version might fix things ... I say might because the download mechanism has changed so we could avoid the same issue, but without knowing for sure what is causing the issue on your end, I can't promise anything.