I was terminated from my job in January - in WA state. My question is, is a company required to pay you the vacation pay that you have coming to you? The company I work for says it's up to the supervisor, who is refusing to pay me the 102 hrs of vacation pay I had coming.

Not unless the company policy provides for it.
http://www.lni.wa.gov/WorkplaceRights/Wages/PayReq/FinalPay/default.asp