Vorinostat With XRT and 5-FU for Locally Advanced Adenocarcinoma of the Pancreas

* Since we are looking for the highest dose of vorinostat that can be administered safely without severe or unmanageable side effects, not everyone who participates will receive the same dose. The dose will depend upon the number of participants enrolled on the study and how well they have tolerated their doses. * 5-FU will be given intravenously over 24 hours 7 days per week during each week of radiation therapy. In order for participants to be able to receive the 5-FU as an outpatient, they will need to have central line catheter placed. * Radiation therapy will be given once per day, 5 days per week, for 6 weeks. * Vorinostat is taken orally. * Participants will be seen once per week during the 6 weeks that they are receiving 5-FU, radiation therapy and vorinostat.