Generally, people will not click on black or white links. They blend in with the content and people just skim over it. Change your link unit colors to match your link color (green). At the top, you link unit background color is black. It doesn't match your page background color. Change that black to "dark grey". You ad block in the middle of the page is good. It looks like it is floating except the link color is white. Change that to green. Hope this helps your CTR!