i cant find the why im getting this error, can someone point it out please??

I get this:

An unhandled exception of type 'System.NullReferenceException' occurred in WindowsFormsApplication2.exe

in this part of the code:

Code:
vehicleData.Rows.Add(vehicle.TypeDisplayName.ToCharArray(),vehicle.DefaultDriverId,vehicle.VehicleId,vehicle.OwnerId,
                            vehicle.DisplayName.ToCharArray(), vehicle.Description.ToCharArray(), vehicle.Registration.ToCharArray(), vehicle.Notes.ToCharArray(),
                            vehicle.VehicleTypeId, vehicle.VehicleProfileId,vehicle.NotifyDriverOfGeofenceAlert,vehicle.IsProfile,vehicle.VehicleGroupId,
                            vehicle.CreatedDateTime, vehicle.ModifiedDateTime, vehicle.UserId, vehicle.UniqueVehicleID.ToCharArray(),
                            vehicle.DefaultVehicleStateID, vehicle.GISCulture.ToCharArray());

THX

Code:
private void gruposBtn_Click(object sender, EventArgs e)
        {
            var owner_response = proxy.GetOwners();

            if(owner_response != null)
            {
                DataTable vehicleData = new DataTable();
                foreach(var owner in owner_response.Owners)
                {
                    var message_response = proxy.GetGroups(owner.OwnerId);
                    var vehicle_response = proxy.GetVehicles(owner.OwnerId);
                    
                    vehicleData.Columns.Add("TypeDisplayName", typeof(SqlString));
                    vehicleData.Columns.Add("DefaultDriverId", typeof(Guid));
                    vehicleData.Columns.Add("VehicleId", typeof(Guid));
                    vehicleData.Columns.Add("OwnerId", typeof(Guid));
                    vehicleData.Columns.Add("DisplayName", typeof(SqlString));
                    vehicleData.Columns.Add("Description", typeof(SqlString));
                    vehicleData.Columns.Add("Registration", typeof(SqlString));
                    vehicleData.Columns.Add("Notes", typeof(SqlString));
                    vehicleData.Columns.Add("VehicleTypeId", typeof(Guid));
                    vehicleData.Columns.Add("VehicleProfileId", typeof(Guid));
                    vehicleData.Columns.Add("NotifyDriverOfGeofenceAlert", typeof(Boolean));
                    vehicleData.Columns.Add("IsProfile", typeof(Boolean));
                    vehicleData.Columns.Add("VehicleGroupId", typeof(Guid));
                    vehicleData.Columns.Add("CreatedDateTime", typeof(DateTime));
                    vehicleData.Columns.Add("ModifiedDateTime", typeof(DateTime));
                    vehicleData.Columns.Add("UserId", typeof(Guid));
                    vehicleData.Columns.Add("UniqueVehicleId", typeof(SqlString));
                    vehicleData.Columns.Add("DefaultVechileStateId", typeof(Boolean));
                    vehicleData.Columns.Add("GISCulture", typeof(SqlString));

                    foreach(var vehicle in vehicle_response.Vehicles)
                    {
                        vehicleData.Rows.Add(vehicle.TypeDisplayName.ToCharArray(),vehicle.DefaultDriverId,vehicle.VehicleId,vehicle.OwnerId,
                            vehicle.DisplayName.ToCharArray(), vehicle.Description.ToCharArray(), vehicle.Registration.ToCharArray(), vehicle.Notes.ToCharArray(),
                            vehicle.VehicleTypeId, vehicle.VehicleProfileId,vehicle.NotifyDriverOfGeofenceAlert,vehicle.IsProfile,vehicle.VehicleGroupId,
                            vehicle.CreatedDateTime, vehicle.ModifiedDateTime, vehicle.UserId, vehicle.UniqueVehicleID.ToCharArray(),
                            vehicle.DefaultVehicleStateID, vehicle.GISCulture.ToCharArray());
                    }
                    string nombre = owner.OwnerName;
                }