Well, I'll just tell you how I have mine set. I'm using VB, but I don't think it makes a difference. On the properties form, General tab, I have Counter = 1, Pulse Type = Continuous Pulse Train, Polarity = High Pulse. On the Pulse Settings tab I have Clock Mode = Use Frequency Settings, Frequency(Hz) = 1000, and Duty Cycle = 0.5. On the Gate tab I have the Gate Mode = ungated.
Then, all my code does is:
Private Sub Command1_Click()
'Configure the hardware
CWPulse1.Configure
'Start the actual pulse train
CWPulse1.Start
End Sub
Maybe you are using timbebase settings for the clock mode and are trying to use an invalid input for the timbebase? This timebase also depends on your hardware. Hopefully, this will work though.
--Russell