Sidebar issues

With the sidebar enabled, I get it 2 times. 
http://www.geocities.com/justinhyde/withsidebar.jpg [220kB]

Without the sidebar enabled, I get a see through sidebar. 
http://www.geocities.com/justinhyde/withoutsidebar.jpg [202kB]

Using browser as below
Mozilla/5.0 (Windows; U; Windows NT 5.1; en-GB; rv:1.7.10) Gecko/20050717 Firefox/1.0.6

Haven't had a chance to view under Ubuntu yet.

Any ideas
Justin