You are trying to use Fax Blast and after choosing the attachments etc. and clicking okay you receive "Object Reference" errors.
You must first select the recipients for the fax. Once you do your lookup in ACT!, you still must press the button with the "..." for recipients and you will see the lookup is already selected on the right hand side. You can then click OK to close the recipients box. Then proceed with choosing your attachment and writing a subject.