Affiliate links not working properly - did I set up wrong?

I have an affiliate link set up for this page:

http://parentingsimply.com/workshop-info/siblings-without-rivalry

It shows that as the Target URL

This is the source code provided to the affiliate.

Code:

<a href="http://www.parentingsimply.com/order/aff/go?r=1&i=1">How To Manage Sibling Rivalry Without Losing Your Mind</a>

When I use this link: http://www.parentingsimply.com/order/aff/go?r=1&i=1

It takes me to the home page of the site, not the specific page.

Why not?

What have I missed?

Thanks!

Still needing help with this...

Thank you - it's working lovely now