I, personally, don't record tests. I don't use name mapping. So what I am about to say might not help. But here goes. At record time, the object has a name and stores it in your test. (Script? I am going to assume script for the sake of example but there are parallels in keyword tests.) Take a look at your object browser in the state of the application where the error occurs. See if the parent of the object that was not found has sibling objects of the same name.
The programmers at my company are very fond of control arrays. I believe that is what causes bunches of objects on forms to be of the same name. You need to find the parent object that contains the child object you are looking for. Do a look in the help files for FindChild, FindAllChildren...
Good luck.