Did you expose at box speed or a personal speed? I know one of my camera's shutter is consistently 1/3 less than it should be. Most advocates of the zone system (myself included) stress the need to test equipment/development routines prior to "fully embracing" the zone system to account for just such things. Thus, I know (from testing) that my 90mm lens will require a slightly different setting from my 65mm lens when shooting the same scene (and wanting the same zones).
It is possible your meter is wrong or your equipment is faulty - it is also possible your development routine is different than what the film actually requires or that the box speed of the film is more optimistic than your situation warrants. Either adjust the meter for next time, remember the difference and adjust the exposure next time or test another camera to make sure it is not a mechanical issue with the first camera. The simplest answer is to adjust the speed of the film, as Michael suggested.