Performance Improvement Plan?

I've been in my dept for over 3 years, with the company 5 years. I took this current job about 3 years ago. About a year and a half ago i got a new boss. After a year he promoted me ( i got promoted in June) In october i noticed he distanced himself from me and has been that way ever since. Today he dropped the bomb that I'm getting a PIP and brought up two minor things that i did wrong...in october. Actually i didnt do anythign wrong-i'm just not doings things the way he wants. I have 45 days to improve...and i feel set up to fail. We have a contract employee that he's buddy/buddy with. I think he wants to get rid of me to bring this person on full time. I am speaking with HR again tomorrow. I am tempted to ask his boss about this since his boss hired me. I am putting my resume together. One of the things he wants me to do is beyond my job scope...I am ready for another job, but the economy is tough. Thoughts?