It wept because the ricotta started out wet. Remix it and use it -- it should be fine (just don't let it sit out for more than a couple of hours), although it might make the tart shells soggy if 1) you didn't seal them, and 2) they stand for a loooooooooong time.
Next time, instead of using the ricotta straight from the container, line a strainer with dampened cheesecloth/muslin, place it in a bowl, dump in the ricotta, and let it drain for a few hours in the fridge. That should take care of the weeping problem. And the mixture will be a bit firmer as well as drier.
