Can Google Adsense ads be placed on copied content websites?
Can the adsense ads be placed on auto-generated content blogs?

The answer to above both questions is NO.

Cecelia Choi from AdSense Policy team has cleared in a statement that the sites who lacks self-written matter is not allowed to participate in the Adsense program. Sites placing Adsense ads should have all original articles.

Some people use softwares that grab content from different websites and then they publish them on their own blog. This auto-generation of content is also against google policies. There are also some WordPress plugins that auto-generate text. Bloggers should be aware of these plugins as this can lead to them ban from Adsense.

I am not sure what google is going to do for Forums as many forums have copied content on them.

Let us know your views on this.