I just solved a weird problem trying to access a fixed IP using Telus DSL service. All my cards worked in a Win98 machine, and connected to the correct fixed IP address.
To further muddy the water, all the cards all ran the LOCALnetwork correctly when installed in the SME5.5 box!
SME55 had problems with cards using the Realtec 8139 driver, only connected to the 10.x.x.x login server at Telus, they never registered their mac address to complete the fixed IP connection. ( That is to say, ifconfig shows a 10.x.x.x address and it does work , but only within the Telus login subnet! NO gateway or DNS !)
I finally grabbed an old 10mb card that used the Realtec 8029 chipset and after changing the driver and rebooting, the correct fixed IP address was obtained.
Further research suggests that the LINUX driver for the 8139 chipset has been patched a few times, and I suspect with the latest 8139c version there is still a problem!