400.

Google cannot redirect you to http://www.textbookx.com/single_product.php?utm_source=Froogle&utm_medium=cpc&utm_campaign=price_comp&affiliate=froogle&action=buy&upc=9780419227007&cond=exchange&price=94.00 because the request was invalid.

This might be because the link was created a long time ago. Try your search again on Google.