node not found vs page not found

Core Node erro: When you are trying to view a Core Node page like Category/Forum/TKB/Idea which does not exixts then you will see the Core Node error. 

For example

http://lithosphere.lithium.com/t5/developers-discussion/bd-p/studi

where as the right node name is studio (http://lithosphere.lithium.com/t5/developers-discussion/bd-p/studio)

Page Not found Erro: When you are viewing a message page with the wrong URL you will get the Page Not found Error

Thanks,
Premkumar