Hm, did you install all this packages?
fp-compiler, fp-docs, fp-ide, fp-units-base, fp-units-db, fp-units-fcl, fp-units-fv, fp-units-gfx, fp-units-gnome1, fp-units-gtk, fp-units-gtk2, fp-units-i386, fp-units-math, fp-units-misc, fp-units-multimedia, fp-units-net, fp-units-rtl, fp-utils
I think you have some problem with your fpc.cfg, or there is no x.ppu in $path_to_freepascal/$version/units/i386-linux/x11/