Fedora 10 KDE plasma font rendering issue

Hello.

I've got a new workstation running Fedora 10 linux and I use the KDE 4.2
desktop which uses some kind of new desktop environment called 'plasma'.

If I start up R and generate a plot (for example: hist(rnorm(10000, mean=0,
sd=1), breaks=100) ). The plot appears but all text (the x/y axes, title,
etc..) is replaced by a square box. No font is rendered at all.

Has anyone else got this problem? If so do you have a work around or a
solution?

I'm using R version 2.8.1 installed from the Fedora 10 repositories if that
helps.

Thanks in advance.