Hi GVS,
1. You have to give the two counter groups different group numbers. You can just leave it so that counter 0 is the top and counter 1 is the bottom.
2. You can change the freqout by using CTR Control.vi. There is a LabVIEW shipping example in the Help >> Find Examples... >> Hardware Input and Output >> Traditional DAQ >> Counters >> DAQ-STC. The example is Generate Pulse Train on FREQ_OUT.vi
Make sure you make your freq out value very low to start and then increase it until you get error 10920.
Have a good day.
Ron