Are you using RM2k or RM2k3? One of the two, I don't remember which, has a bug with the font, and there's a patch you can Google to fix it.
I don't THINK these forums support RPG Maker programs prior to RMXP because these were not commercially available outside of Japan, so I don't think we're allowed to troubleshoot problems with said programs. But I do believe that's what the problem is and how you go about fixing it. :)