Thank you for reporting this problem to us. HTML fails to be imported properly due to limitaions of our HTML engine. I have logged this to our defect base as issue #1149. We will try to fix it in our next release which will be in the end of August.
I also had a look at this html file. It is now imported to Aspose.Words without throwing errors. It is also exported to PDF okay. However, there is a lot of CSS formatting using styles that Aspose.Words does not yet understand. Only inline CSS styles are supported. The new version of Aspose.Words that will come out soon certainly imports this HTML better (tables etc) but support for CSS styles is still not that rich to import this document well. It will remain on our task list.