Fix up a few coding issues:

 - Remove a redundant if check on the objectId in the third segment.  This
shouldn't happen anyways.
 - Remove an unused variable.
 - Correct a comment from a copy+paste error.
 - If properties are not found (not that there are none), then throw an exception.
 - Use the classname as found in the MCOS section, to make finding errors easier.
 - Even though it isn't used, store the segment 2 index for object properties,
   for the future.