Hmm, I didn't change how this was displayed from the regular checkout. I'd have to see your checkout page.

Disabling ENABLE AUTOMATIC REDIRECTS doesn't solve the problem. Turning off ENABLE SEO URLs did make the Fast and Easy Checkout module work. But is it worth disabling Ultimate SEO URLs though? I heard that SEO URLs are not so important nowadays. Is it true? Please advise.
SEO URLs are not as important to Google as it may be to other search engines.

I will try and find the fix for you...