figured out the problem. i had a large slice i had used to export a demo image of the design. even though i had the slice layer turned off, it would not let me export the other lower level slices.
in my opinion, i think if a layer is off, you should be albe to export whatever layer you want.
this is the second bug i've found.
You cannot overlap slices.
It isn't a bug that you can't. If you have overlapping slices, then Fireworks cannot determine how to slice the document to produce a layout. Slices being on or off doesn't change that FW still needs to set to be able to work out how to slice the document into an HTML table. If you have overlapping slices, then it can't be done, and FW will balk. Because the slice-to-table layout was the original intention, disallowing overlapping slices is not a bug.