BB freezes when running samba and transmission

Hi all,

I'm trying to use my BB (xM Rev C) with the transmission bittorent
daemon and with the samba daemon.
While the board works well if only one of the daemons is runnig, it
fails when transmisison is
downloading torrents at the same time when I try to upload load large
(>= 1,5 Gig) files (I've connected a ISB disk to the BB).

Samba quits the connection and most of the time the board completely
freezes without recovering.
All connections including ssh drop and board can only be reacivated by
pressing the reset button.

I tried the ubuntu-11.04-r4-minimal-armel demo image as well as
various angstrom builds. All show the same behaviour. I also tried
different transmission versions up to the latest 2.33 (samba is
3.5.8).

Does anybody have an idea what the problem could be?

Thanks in advance,
Kurt