I have been away for 5 months and found this error after updating plugin
96 CarTurrets - Failed to compile: Argument 1: cannot convert from 'ProtoBuf.PlayerNameID' to 'ulong' | Line: 1211, Pos: 50

Any help would be appreciated

You probably didn't update the plugin. Maybe you downloaded it but didn't install it.

from plugin folder
namespace Oxide.Plugins
{
[Info("Car Turrets", "WhiteThunder", "1.6.5")]
[Description("Allows players to deploy auto turrets onto modular cars.")]
internal class CarTurrets : CovalencePlugin
{

The plugin no longer has any code referencing PlayerNameID, so the above error isn't possible. There may be something deeper wrong with your server if changes to the file system aren't taking effect.