The Print Prebills screen has a number of options on it that control whether or not a Prebill prints.
Some things to double check are:
1. Your billing cycles – do you have them all selected?
2. Are you choosing to suppress prebills that have no WIP?
3. Are the Matters selected for Billing – have you clicked on the Select/Defer button to double check that the Matters are selected?
4. Are you selecting the proper Fee Arrangements?