The Odo theme that comes with gtk-engines makes all gtk text-entry boxes garbled and unreadable.
I am not sure which entry boxes you mean - the entry boxes in the theme selector preview are legible. Some themes are just a matter of taste and its up to personal preference if you like how they look or not :) That doesn't make it a bug necessarily.
I've put up a small screenshot of the problem at http://torsion.org/redhat/ You can see that it is indeed some sort of bug, and not just a matter of taste. :) I did nothing special to get the problem to show up. All gtk text boxes, including the theme selector preview, exhibit this garbled text, as long as Odo is in use.
Odo was not shipped in 6.0 because it does not work.