Now, it works also for me with ibdump 2.0.0-5 (the one included in MLNX_OFED 2.0-3.0.0).
So it seems there is a regression in ibdump 2.0.0-9 (the one included in MLNX_OFED_LINUX-2.3-2.0.0)
I can see my network trace in wireshark with no problem. that's great..
Thanks a lot