PCI-6133 always returns huge constant number of counts

Hi,

I am trying to use a PCI-6133 with a BNC-2110 adapter to counting leading edges of pulses.  Please excuse my high degree of ignorance of how to do this.  Anyway, I connected up my TTL input signal according to the BNC-2110 instructions (to PFI-8 via User-2). Whenever I run the DAQmx sample program Count Digital Events.vi, it recognizes the PCI-6133 OK, but always returns an absurdly high and constant number of counts, like 3.2e9.  The number doesn't change as I send test pulses into the input.  It also remains the same even if I disconnect the input line entirely and rerun the sample program.

Rebooting yields the same behavior.

Using DAQ assistant to generate my own code, instead of the sample program, produced exactly the same result.

Thanks for any help you can give me.  I don't even know where to start to debug this problem.

Thanks,

Andy