This particular script (orkut-community-downloader) uses "automate-save-page-as" script to download every single page, and therefore contain the (simple) logic for navigating through all the posts, polls, and later on changing the links to point to local copy, symlinking stuff to save space, and providing support for "resuming" the download operation.
Do you mind sharing what bugs you are facing (and which platform you are testing on), so I can try and fix them ? If HN comments doesn't seem a fit place, then feel free to email me (ID: <username>@gmail.com).
* PhantomJS[1] (with or without the facilitator CasperJS[2]) -- in fact I'm kinda motivated to write a script myself using CasperJS to save my communities, now that you remembered me they are there waiting to be saved;
* Selenium[3] (I never looked at this, but it seems interesting as it holds the slogan "Browser Automation").
[2]: http://casperjs.org/
Good luck with your CasperJS approach, and I would love to learn from it if you wish to share the code later.
Seems like if they were still active, easing this kind of export would be within their stated goals?