faxing with Exchange

In my company we have setup windows fax with our Exchange 2007 and all
current machines work fine. however, we recently setup and configured all new
computers. I installed the exchange fax as a printer and have installed the
windows fax. But I can not get the faxing to work.
All Domain Users have priviledges to manage docs and print.
All other settings seem consistant with the configuration of the old
machines. What am I missing? Or is there some update or registry change that
I need? Thank you in advance for any information general internet inquery is
not proving helpful.