Assuming you have reconnected to the Exchange Server and are under these same security requirements, I do not know why you cannot veiw your files. I hope it isn't anything irreplaceable that you don't have backed up somewhere.
Going forward, take a look at Enhanced Email for Android. Yes, it is a paid app, but it gives you the choice of enforcing the Exchange Security rules on your device. My work's exchange server required a PIN or password phone lock. It is very inconvient to have to put in a PIN every time the screen times out. With this app I still have access to the Exchange Server without having the phone lock all the time.
