Wierd anyway. I've fixed the error. just been messing about trial and error and now its working.

Code:
objCommand.CommandText = "Update [All] SET Card_IP_Unique = '" & Card_IP_Unique & "' WHERE IpAddress = @IpAddress AND CardNumber = '" & LabelSuccess2.Text & "' "
objCommand.Parameters.AddWithValue("@IpAddress", ipaddress.Text)
'objCommand.Parameters.AddWithValue("@Card_IP_Unique", Card_IP_Unique)
 objCommand.ExecuteNonQuery()
Thanks for looking and your help