usb device stack init fails

With S7G2 and SSp1.2.0b1, I just created a UsbDevice thread. Since I plan to use my own Vendor commands for all USB communications, I did not add any USB device class. When I run the automatic generated code, it fails at

         status_ux_device_init = ux_device_stack_initialize( (uchar *)device_framework_high_speed ........);

         if ( UX_SUCCESS != status_ux_device_init ) {

             ur_device_error_callback(....);

          }

status_ux_device_init returns 0x42 corresponding to UX_DECRIPTOR_CORRUPTED.

Does anyone know what could cause this error?  Is there a way to jump into the threadx source code to see why it fails?

I also see there is a function created in common_data.c but not called: _ux_dcd_initialized(). Do I have to call this function in my thread? 

Thanks,

Jimmy