you have rate at LEAST one of the two [Default being the sig.] to the person above you.
So if someone doesn't have a sign then rate the Avatar, Otherwise the sig has to be rated first.
[Example] (both):
Sig: ?/?
OR (N/A) <- if not applicable
AND/OR (not needed to be included)
Avi: ?/?
OR (N/A) <- if not applicable
(Personal note: I dont care much for my avi, I made that alot older then the sig, so I might eventually re-make my avi. lol)