I am under contract which lays out the rules for my evaluaion. Can my immediate supervisor ignore the contract?

The more important questions are why your supervisor has ignored your previous performance goals and how this has affected you.  If the motive is based on some type of discrimination (race, age, etc) then you may have a claim.  In the absence of discrimination, then at a minimum, there must be some financial injury you suffered such as loss of a bonus or a raise.  You should discuss this in more detail with an attorney.  You should note that if the contract you refer to is just an employment policy handbook or something noted on the last evaluation, this may not constitute a contract that is enforceable.