I don't know if this is related, but you may also check with your hosting provider to see if they have turned on mod_security on your site. I ran into something similar to this (at least the pink errors ) due to this change and it broke everything all of a sudden for me...
In short, I've noticed with Abantecart, if only you get a new problem, it's probably local to just your environment or the hosting provider messing with their settings...and breaking your stuff (!, yeah, it's frustrating as heck)