Fonts do not display properly on Red Hat

Hi

I'm using R version 2.3.1 on Red Hat Enterprise Server 3. 

When I run a simple:

plot(1:10,1:10)

The plot comes out great, but the fonts are displayed wrongly:

http://coxpress.sourceforge.net/test.jpg

I realise this is probably not an R problem per se, but before I go messing about with my fonts, can someone tell me which fonts R (or X11) is trying to display, where they might be installed and any suggestion as to why they're not being displayed properly...

Thanks
Mick

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