Sorry, but I don't don't think there is such a thing as common interview questions for SAS admins. Interviews, if done properly, are not exams where you have to get answers right. They are conversations to try to find out your competencies regarding SAS administration.
If certain technical questions are asked, I can only advise you to be honest. If you don't know the answer say so. But there is no harm in saying you know where to look to find the right answers. Searching support.sas.com is a good startiing point. Being able to search SAS Notes for known problems and fixes is a must. Knowing how to track a SAS problem is essential. Knowing how to go about solving an admin problem is far more important than knowing the answer straight away.