Hi Chris,
Sorry for the late reply here, but this seems like a problem that was
introduced with ESX 3.5U1 and it is also still the same in U2.
While vmktree is working perfectly for ESX 3.0.x, supporting 3.5 has
been harder than I had expected because of several such strange things
that have changed. It also seems that networking graphs on 3.5 are
affected while cpu and memory are correct.
I'm currently reimplementing the collection of these stats with an
alternate method and I will probably release an updated release in a
week or two.
Lars