I'd be thankful if you could get the release candidate a try and - in case - let me know about any problem you encounter while doing so.
You may get the release candidate code with
http://tdom.org/index.html/zip/tdom-0-9-1-rc/tDOM-0.9.1rc.zip or http://tdom.org/index.html/tarball/tdom-0-9-1-rc/tDOM-0.9.1rc.tgz
See the CHANGES file for the most important user visible changes.
With tdom 0.9.1, I was able to play with rl_json beautifully a few weeks ago! https://github.com/RubyLane/rl_json