s2gx evm usb comm with Labview

I would like to talk to the s2gx evm via the on board USB. It is hooked up through a FTDI2232. I called the FTD2xx.dll in labview to open and write to the device. But I am luck to open it one time every dozens of tries. Most of the time the FT_status returns 1 or 2. How come?

Thanks very much,