From the select tag, from my own observation, it appears that you have called the wrong tag "name" from the dropdown. Instead of

if($_GET['Solicitations'] == "Bid")

Since the "select name ="SType" ", why not use

if($_GET['Stype'] == "Bid")

. I think that is where the mistakes comes from. Because it is whatever value you select from the dropdown that becomes the value of the Select tag.