The error 2 message you are seeing is actually a spacing and sensitivity error. The instructions that you received have been updated and are available on our website. The only major change is the error messages. Vertical distance or the space between the bullet flight path and the top of the sensor deck needs to be between .125 and .25" One of the two rubber V block pads should get your between that threshold if you barrel is between .5" and 1" in diameter. horizontal spacing (the space between the end of your rifle and the beginning of the flat portion of the sensor deck) needs to be between 1" to 1.5" If you are shooting .30cal and larger; start with a setting of REG (regular). If you are shooting .30cal down to .223, start with REG and then try HI 1. If you are shooting .223 and smaller, start with HI 1, but you will most likely need to use HI 2 for smaller calibers like .22lr. If confirming spacing and sensitivity settings doesn't work, please contact us.