Some further information I discovered. dmesg shows this
sis190 Gigabit Ethernet driver 1.2 loaded.
ACPI: PCI Interrupt Link [LNKD] enabled at IRQ 3
PCI: setting IRQ 3 as level-triggered
ACPI: PCI Interrupt 0000:00:04.0[A] -> Link [LNKD] -> GSI 3 (level, low) -> IRQ 3
PCI: Setting latency timer of device 0000:00:04.0 to 64
0000:00:04.0: Read MAC address from APC.
0000:00:04.0: Can not find ISA bridge.
ACPI: PCI interrupt for device 0000:00:04.0 disabled
sis190: probe of 0000:00:04.0 failed with error -5
I'm sure this is the problem - but how do i fix this?