I only quickly glanced at your homepage. It seems like you could be getting objections from visitors to sign up for the ebook because they don't understand the value they may get from it. Is there anything you can add to that form to sell the ebook better? Have you tested using other guides at all?
In what way are the 98% of leads unqualified? Maybe you can better qualify the leads when addressing how you pitch the ebook or what other guides you test.
Also, could 98% of the leads be bad due to where your traffic is coming from? Have you looked closely at where the good leads are coming from? Can you grow that referral source?