Yield not working upgrading to rails 3

I am currently upgrading an app to rails3 and have run into a weird
issue where my main content will not yield. I get nothing rendered to
the page. If I use content_for I can get it to render fine but the main
yield does not work. If I generate a new app things work as expected.
Any suggestions on where to look? The log says it is rendering and I get
zero errors...

I am having this exact same problem. Any news on it or perhaps you
found the problem or a fix?