6218 only one of two counters works

All-

    I am using the two counters on my USB 6218 simultaneously.  Counter 0 works, while counter 1 does not for the standard input.  When I switch counter 1 to the timebase, it counts the timebase fine.  When I switch it back to the standard pin (PFI3, I believe), it does not count my pulses.  However, this same pulse source counts fine on counter 0 on its standard pin.  Any suggestions?  It worked fine, but now I have changed computers (and no longer have access to the old one).  LV 2013, daqmx15.?.?  J