Hi ErnestV,
It looks like your TKB may be private, so unfortunately I'm not able to see all the links you provided. From your sample REST API call though, the error seems to suggest that there is no node with the id you specified. I would suggest double checking the id of your TKB. Please note that this is the ID specified when you first created the TKB, and will be different from the title that you've added for the TKB.
If you don't recall what ID you used for the TKB, you can browse to the front page of the TKB and examine the URL to determine the ID. For example, here on the Lithosphere I can browse to the front page of the Developers Knowledge Base:
http://lithosphere.lithium.com/t5/developers-knowledge-base/tkb-p/studio%40tkb
The very last part of the URL, after "tkb-p" is the TKB node id. In this case, it's "studio%40tkb", or URL decode it's "studio@tkb". Please also note that if you've created a stand-alone TKB node (instead of being associated with a board), the TKB node id may not necessarily have the "@tkb" suffix.