RE: casterconcepts.com
I would definitely say it is a linking problem - I can't comment on adwords effect as I have not used it. As you say above G is showing very few links - 4 by my count. This is quite poor for an established site and MSN show 850 - so somewhere along the line G is not crediting your links.
The result is most of your site is in supplemental index, (try site:your domain) so won't usually show up in serps! We've been there so can sympathise. Only tips I can give is use unique title tags - usually for one idea/prduct per page. I also think it helps if you have a description that includes the keyword and also put in url if possible. We're not an
SEO company but managed to get a few pages out of the SI. Yeah - also get quality links or change strategy - you've got plenty of links but they don't get recognised - not sure why!
Regards