The correct function to use is E Series Calibrate. In the past, this 10840 error is returned by the E series calibrate function when the EEPROM of the board needs to be reprogrammed. To fix this problem, call customer support to send the board in (http://sine.ni.com/apps/we/niae_asc.main).
If you cannot wait for the board's EEPROM to be reprogrammed, then consider using averaging several datapoints rather than using single datapoints to lessen the offset in your results. There are other sources of bad readings besides the need for calibration. Check out this webpage for more troubleshooting advice:
http://digital.ni.com/public.nsf/websearch/cb279761ae4bc61186256a38005444c6