This type of error occurs when you don't define proper url for your page. Check all url in you page.
Always provide full path url for your page then this type of problem will not occur.
eg:
<a href="http://www.yoursite.com/Secure_Page/default.aspx">Home</a>
<a href="http://www.yoursite.com/Product.aspx">Product</a>
Refer:
Navigating from one page to another page[
^]
I hope it will help you.
Good luck.