I've already checked this out, but it doesn't help, since I already applied the solution suggested.
Here's what I have; there's no fill despite it being constrained to 2d and the fill option being selected. Not sure if this is relevant, but it was originally modeled on the XZ axis, but I rotated it onto the XY one. I made sure the curve was closed as well (toggle cyclic doesn't solve the problem). Help would be appreciated.