[oscarjh]

I think pitching is your problem.
Your team is 9th in run production which is pretty good.
On the other hand, your pitching is around 16th in the league (overall), your closer is only doing his job 69% of the time, your set-up man has a high OBP vs. lefties and righties and the rest of the pen is poor. You do have 4 good starters in Martinez, Schilling, Perez and Meche.
Being that the trading deadline is past and you cannot call-up or demote players during the playoffs, I would set my rotation to 3 or 4 men, and on the team strategy screen, set the "pull starters" function to very slow hook, hoping that my starters can go as long as possible before turning it over to the pen. I might even consider a 3-man rotation and using Meche as the primary reliever.
Good luck.