I'd hate to be a whiny bitch, but I spent hours trying to figure this out, and I love Inkscape to death and use it fabricate all sorts of crazyhttp://www.flickr.com/photos/laughingsquid/506980536/ shit http://www.coreyfro.com/heart/dscn2835.jpg.
I finally got-it(tm)http://www.coreyfro.com/images/Critically%2520Single/24x18%2520critically%2520single.svgbut there needs to be better docs or an easier way. As intuitive as most of Inkscape is, when it comes to text on path, the software can behave very unintuatively, and the basic method just is annoying.
I was obviously trying to put text on an oval. The trouble I had was positioning text on the arc. The solution is make the oval you want and create the beginning and the end points, but this isn't readily apparent. My own error is that in the past, I have put text around a circle, so before I would simply rotate the circle until I was happy with the position. I think I got this method from a tutorial. With an oval, though, this doesn't work.
Still, it would be nice to be able to scoot text around on a path so one doesn't need to tweak the perfect path for the sake of positioning text.
If there is a way, please let me know, and please document it. I couldn't find it for the life of me and, for the first time ever, I starting screaming profanities at inkscape