The decision on my form is “Applicant withdrawal-pre-admit”. I called and they’re closed until January 4th.
I can’t find anything on the part of the website that describes admission decision definitions, but from what I can tell it sounds like you withdrew your application before they could admit you… if you didn’t actually withdraw your app definitely call them after the 4th because it could be a simple computer mistake
http://www.admissions.purdue.edu/apply/applicationstatus.php