Duties removed and deemed unqualified

I work for a large accounting firm in Maryland. I started in March of 2004. Less than 60 days ago I received a wonderful review, salary increase and a large bonus for all the work I had done over the past year. In my review there was also a paragraph that said all of the projects I was working on were complete so now they wanted me to focus on another role that is totally different than the one I applied for. In the meantime, a position has been created for the duties my boss no longer wants me to perform but they are the same duties she just gave me a wonderful review on and said I did a fantastic job putting these procedures in place. One of the duties in teh job description I created an implemented at the firm. It is brand new. I love what I was doing more than what she wants me to do so I applied for this new position. My boss denied my advancement and told me it was because I was not qualified to do the job. One of the requirements of the job description is to have a degree in marketing and I do not have this. I questioned her as to why I am suddenly not qualified when she just had me doing the job she replied "you have to have a degree, there is no discussion" Meanwhile not one person on the entire marketing team in this firm has a degree in marketing. They have degrees in English, Criminal Justice, etc. but not markeitng. She said they were not hired by her, they were employed before she got to the company. I went and spoke with the Partner in charge of Human Resources and she basically said my boss woudl not budge and she advises me to take a severance package. I declined the package because I just didn't feel it was right. When my boss found out I went to HR, she started to make my life a living hell. She pulled me in her office and told me that I should realize I have options now but if she isnt' happy with my performance in 30, 60 or 90 days I will not have these options. She said I probably didnt' take the option because I thought I would be out on the street and that is not the case and she advised me to revisit my options. She also said she wishes I could talk to her last assistant at a competitor firm she came from so I could see how she liked things and do them the same way. I documented and dated this conversation and made my HR rep aware. She now has told me I do not communicate, I am unqualified to do the new position she has layed out and basically everything I do is wrong. This week out of the blue I sat in her office with another Manager and she talked about the communication "problem" we are still having. I had no clue what she was talking about. Every instance she used she was not available to speak with but said I need to make her talk to me. This lady has a repuation throughout the entire firm of being difficult to work with and nasty and I am sure everyone will attest to this. One of her colleagues even went as far as to give my resume and phone number to a recruiter to help me find a new job. (this was with my consent) I want to know if I have any kind of case here or if I should just revisit the severance package? She has done this to another employee when I first started but they foudn placement in another area of the firm for this employee. Now it's my turn but there is no where for me to go. I am documenting everything but want to know if I have a chance at righting a wrong. I think they are setting up to fire me which is the basis of her having this conversation with me on how I still am not communicating.