You need to provide more information. Seems to me you are having configuration problems, SMERFax will only allow you to use the ttys0 ou ttys1 ports, if these ports were already setup for the printer, then there's your problem. If you need to use some other port for fax (I use ttys5 on a internal modem), then you need to edit hylafax.conf manually.
Basic troubleshooting will be checking logs after request a service from either application.
HTH,