Connecting Multiple DV Converters for use with IMAQTOOL

Hi,

I'm trying to connect two digital video converters to capture images from two analog cameras using the image acquisition toolbox. I'm able to connect one and capture images fine. However, when I try plugging in the second, I get the following error:

winvideo: Image acquisition device is not accessible. Insufficient system resources exist to complete the requested service. Make sure no other objects or applications are accessing the same device.

The DV converter that I am using is a ADVC55 from Grass Valley and I am daisy chaining these through a firewire hub. Any help would be greatly appreciated!

Thanks in advance,

Doug