Unless you have less then 4GB of mem I would not switch to 32bit mode as I have not seen issues with 64bit and the Intel - in fact you need 64bit mode to work with Intel's I/O AT for performance.

I have in some cases seen strange issues with 802.3ad (not sure if it is NIC or switch or Jumbo) and would recommend the Balance rr to test. Most of the crashes that I have seen have been hw releated but I would need to investigate the ticket where you sent in the logs.