We have a client that has been seeing that error in version 5.1.5 - it has to do with the registry entries that document the path.
AC spent a few hours with me changing the path back, but invoking the eRX printing within AC somehow over-wrote the path. We never found a solution, and we have been waiting for version 6. May be they are still waiting until this gets resolved. They have stopped using those machines for printed prescriptions.
In that case it is on two Vista Business machines.
