Looks like patch submitted by Li Ding to the list works, I applied it to the trunk:
Markus, does this fix the problem in general or there is something still missing?
A few people contacted me directly regarding the broken vocabulary import functionality being broken in SMW.
Here's the discussion about it with Markus's comments about the reasons:
I've created a bug for it in Bugzilla so it's easier to track and fix:
You can see an example of broken RDF Export here: http://www.techpresentations.org/export.rdf (it's 14M of RDF/XML so your browser might not be very happy displaying it, compressed version is here: http://www.techpresentations.org/export.rdf.gz - 1.6M).
Markus, could you please give a bit more explanation to how you think it should be fixed.
I think it's quite important problem and might stop some Semantic Web efforts from using SMW because of this "open world incompatibility".
I'll be happy to write some code to fix it, but my understanding of SMW inner workings is quite poor at this moment so I'd love to get some explanation ;) If somebody can fix it without me writing code (which will probably take forever), it'll be even better ;)
I also saw this post to the list: http://article.gmane.org/gmane.comp.web.wiki.semediawiki.devel/1493 but couldn't figure out if this is related and what is the long term solution.
Will appreciate any feedback!