ESD affecting DAQ USB 6002

Hi, 

I am using the USB-6002 DAQ in a system. My system connects to some of the analog and digital pins and then the DAQ is connected to the Tablet via a USB cable.

All this is fully enclosed in an ABS enclosure.

Each time we run ESD discharge test of 8kV in air near the enclosure, the DAQ freezes and only a power cycle will get it going again.

I get the error message 

7220005 (append)

Code d-50405

Any idea or suggestion will be very much appreciated.

Thanks