Hi Suzanne
Flow can be frustrating, If the text flows sideways or in reverse, you may have to rotate the text planar surface 90-180 deg or even end to end or pick opposite ends for the flow surface and target surface.

I use it all the time and it still only goes perfect 1/2 the time

If you don't know already, to form your planar surface the unwrapcurve command is great for generating a line thats the length of a curve off your ring surface or edge (also off the curve on the outer ring surface)

shayne