This error seemed to have popped up with the new upgrade...It sounds like you can ignore it for now and the devs maybe trying to find more security checks within Abantecart...
No idea how good/bad Prestacart is, but I tried to research most of them prior to using Abantecart myself and went with that...
Some old messages state Prestacart is very slow on the backend (I just did a quick google search) and had massive inventory stock management issues last year...)
Like with any cart program, good developers can probably make any of them work.