This is what I got at that link:
<CENTER>This link is not valid.<BR>Click <a href="http://www.compusystems.com/order">here</a> to continue.</CENTER>
This is the link I found:
https://www.compusystems.com/servlet..._utmk=72904080
Then click on "Register" under Attendee
Right at the top it says: "AAPEX and the SEMA Show are closed to the general public" and there's a list of verification paperwork you need to submit (two items) to qualify. But like I said, I'm sure people can get in if they have an "in"