Ni VMS view acquired image output is 480x0

I've been trying to grab a single frame on an NI-1491 HDMI analyzer using the "VMS view acquired image" vi available here:

https://decibel.ni.com/content/docs/DOC-29335

it runs with no errors and the "niVMS Configure Devices VI" subVI seems to initialize the HDMI input just fine, but the output of the "VBF to Image FIle" subVI in the block is outputing a 480x0 image, which is...less than helpful. It seems to be grabbing a single frame just fine in the VMS standalone app, but the LabVIEW VI's are not happy.

any ideas?