PHP problem

I have an existing php application, I am having a issue with select box loosing values when pressing submit. The problem can be seen at <[login to view URL]> On selecting the value from the first drop down the second drop down is populated from the database. On pressing "Generate Table" The value of the second drop down disappears. I want someone to look at the attached php file and figure out whats happening. An experienced php programmer will know the problem right away