Hi Figo,
The PCI-6509 is a NI-DAQmx only device. This means that you cannot use it with Traditional DAQ. Since DAQmx will not run in LabVIEW 6.1, you will not be able to program your 6509 in LV 6.1. I would highly suggest upgrading your LabVIEW version to 7.1. This will allow you to use NI-DAQmx. As you may already know, all new NI devices will support NI-DAQmx. As Traditional DAQ is phased out, your LabVIEW 6.1 code will not work on new devices. It is best to switch over to LabVIEW 7.1 and DAQmx as early as possible to reduce the amount of code that will need to be rewritten in the future.
-Sal