INPA stops during reading analog values

I got this cable

http://www.ebay.com/itm/BMW-USB-OBD-...b475a7&vxp=mtr

Installed the software and INPA seams to be working correctly but when the reading the analog values 1 and so on it will read correctly RPM,Voltage, ETC for a few seconds and then stop and give me a error message 20. Stop and not read no more live data and the readings go way down to almost zero and not read live data anymore. Anyone ever had this issue and fixed it or know how to fix it. Thanks

Check your car battery....it's dying.