Glut Fonts Irratic?

Has anyone else found glut fonts to be very flakey? I like to use them to label objects in 3-space. The problem is that they often simply stop appearing on the screen when I (we) make changes to unrelated parts of our programs. We are using Visual C++ on Windows 2000 and XP. The problem seems to be worse when we try to use different font styles in the same program. A few days ago I ported an OpenGL simulation from a Win 2000 desktop (NVidia video board) to a Win XP laptop (ATI board). All my Glut labels worked fine on the Win2000 machine, but about half of them stopped appearing on the Windows XP machine. Has anyone encountered similar problems and found a solution? Thanks.