I would just remove and reinstall the valve cover gasket just to make sure it is seated correctly. You might even as well replace the gasket while your at it.

The early Aveo's and GM's in generals are known for throwing the low oil pressure light for no reason. You can replace the oil pressure switch in your driveway and the part itself is only $20 or so. I did a write up a few weeks ago on it too. Here you go; http://www.aveoforum.com/forum/f94/h...-switch-16854/