ClickBank is a prohibited site. From HubPages FAQ...
"Links to sites that contain links to any of the above (ie, a blog that links to an ebook sales page, etc)
Commonly used affiliate programs are evaluated based on the totality of how they are used on HubPages. While some of the offers or sites promoted may be ok, if a preponderance are not, then they may be prohibited anyway. Clickbank is an example of this."
Hope this helps! ;)