It was working for me on MLNX_OFED 2.0-3.0.0 on Ubuntu 12.04.
Now that I upgraded to the latest version of the drivers (2.3-2.0.0), I got the same error as the one you got.
However, if I use the ibdump package included in the MLNX_OFED 2.0-3.0.0, it works even with the latest drivers (2.3-2.0.0)!