SDL_ttf -> TTF_SizeText() error

I’m running Suse 10 (Linux), using g++ to compile my SDL program.
On checking the size of the text on a surface, i get this error:
SDL_GetError() = Failed loading DPMSDisable: /usr/X11R6/lib/libX11.s o.6:
undefined symbol: DPMSDisable

What is the problem, or how would i solve it? I’m not an experienced linux
user, so i’m not sure what i have to do.