Global Village's implementation of arbitration depends on a component of ARA 2.x called the "Link Tool Manager" which is not present or used in OT/PPP or ARA 3.x. Notice was given to all developers that this component would not exist in ARA 3.0, which is a complete rewrite and uses Open Transport for access to serial ports, rather than accessing them directly. ARA 3.0 was seeded very early to developers to identify issues and work on solutions.
Apple and Global Village are working on a technical solution to allow ARA 3.x and and updated Fax software to co-exist on the same system. We do not yet have an estimated date when this will be resolved. In the interim you can revert to an earlier version of ARA, or put ARA servers and FAX servers on different machines.