The virtual switch you are trying to create is trying to access the 2529 using Traditional DAQ, not DAQmx. The Switch Soft Front Panel is built on DAQmx, which is why the switch SFP works fine.
Check the driver sessions and logical names associated with the other switches in your PXI chassis and see what is different about the 2529 logical name and driver session. Make sure you are using DAQmx for everything (if that is what you are intending to do).
I hope this helps. Best of luck with your application!
Gary P. Applications Engineer National Instruments Visit ni.com/gettingstarted for step-by-step help in setting up your system.