Weird behavior with FreeBSD 5.4-REL on a Dell Inspiron 10000

[Baldur Gislason]

I tried FreeBSD on a Dell Inspiron 1000 laptop. Every time I tried to use the onboard network device, sis0 the machine locked up.
It is fine until I configure the interface up and plug the network cable into it.
Also, when I boot without ACPI it locks up in the booting process.
I have also tried NetBSD, no problems there but when I configure the interface up it does pop a message into dmesg:
sip0: transmit FIFO underrun; increasing Tx drain threshold to 1536 bytes

Any input?

Baldur Gislason