Re: help with custom theme breakage
First glance at this and the HTML seems wrong and might be difficult to fix with CSS.
The left sidebar should be inside the same container as the activity stream and the right sidebar. Looks like its inside the same container has the widgets across top.
Basically you are trying to put a square inside a circle.
Another thing I want to point in general. If a theme has .fix or .clearfix all over it. Then run the other way.