the plugin loaded once for me then I too get can't load plugin.
And I seem to have decoding problems. I think or I did mess up with mkvextract or I hit a b-frame or something not that good in this stuff
Anyway it's a x264 encoding so some features of x264 are not implementet in libavcodec yet or something
Edit ok just checked using DirectShowSource and that decodes fine. So I guess it's a decoding problem.
Runtine is wrong too.