Hiding register button in first sidebar

I created a sub-theme as shown in "How to override the page template with a page.tpl.php file".
I did that because of hiding the register log in / register button. Of course it is possible doing that by CSS.

But I'd like to do that via modify the sub-template. So I did the steps as described in the tutorial. Then I defined the original theme as base theme. After loading the new sub-theme the layout crashed.

Is that the right way to hide things from the original theme?