PDF axis numbering messed up

Hi all,

I've been making some plots with transparency and realized that in order
to get a vector output I have to use the PDF backend instead of PS.
However, the PDF plots have axis labels that are messed up. Instead of
showing "10^3" it shows "10_3", ie all exponents are subscripts, and the
axis numbers are at the top instead of the bottom, so they clobber the
graph title. There must be something not working right, because it's not
usable the way it is. Can anyone suggest fixes?

This is with 0.90.0 on a FC6 x86_64 machine.