fda tool not meeting frequency specifications

I'm developing an audio equalizer using MATLAB's fdatool, and I'm noticing some very strange things are happening. For low-frequency bands (25, 40, 63, 100-Hz), fdatool simply doesn't match the frequency specifications that I input.

For example, if I try to create a Butterworth IIR LPF (fs=44100-Hz, fc=30-Hz, order=10), the magnitude response shows a filter that starts at 0-dB at 0-Hz, then the gain drops off linearly until I have about -200-dB at 30-Hz. Obviously the filter doesn't work, and I've verified that the magnitude response plot is indeed accurate to how the filter performs.

The odd thing about this is that if I use someone else's computer (running the same version of MATLAB), fdatool works perfectly and produces the magnitude response I am looking for (and sounds great too). I can't see any specifications that are different in any case.

It would be great if I could resolve this so that I could use my own computer to finish this project. Maybe someone else has experienced this as well? I am running R2010a.