Can glReadPixels fail because of the video card?

I wrote a OpenGL program, using glReadPixels(…) to get some information. However, the program works fine on some computers but fails on some other computers, especially on laptops. I checked my program and found glReadPixels(…) failed to feedback the information I needed. Is the problem related to the video card?

I found glStencilFunc() also failed on some systems!