"ERROR" when I try to upgrade to Lollipop 5.1 on my Moto G, xt1032 (first gen).

[AC Question]

I got a notification saying software update available, so i start to update to lollipop 5.1 and then halfway through the update it says error and starts my phone back up. I was rooted the first time, so i unrooted via the super su app. That didnt work either, so i factory reset my phone, yet it still says "ERROR". Why? Can someone help please. URGENT.

Thanks.