Dear Saar,
the black strip with text at the bottom of Kabuki demo front page is the copyright area, and it indeed might be a good idea to use it in your case: please visit the Theme Options panel, “Page Elements” tab, the “Copyright text” field at the very bottom. You can also revert to the “Background Slider” template for the page since the copyright will still be displayed. The notices you’re getting at the moment are WordPress’ responses to the fact that no widgets were located in the sidebar widget area while the page layout you chose apparently contained a sidebar.
Let me know if the copyright area solves your problems!
Sincerely,
Andrew | Satori Studio