I work for a large company in PA. They have decided to shutdown for maintenance two times this year. There will be no production work available for me. They have told me that i have to use my vacation for these shutdowns even though work is not available to me. Shouldn't i be able to file for unemployment comp. instead of using the vacation that i earned?

That is the company's option. Since vacation is not a benefit that has to be offered by law, the company can determine how it must be used.