I have had constant problems with the DE538 network card in my desktop pc working under Windows XP but not under ubuntu. Today I snapped and spent a precious £7 on a new network card. Problem solved. It's a generic card based on the Realtek 8139 chipset revision D. The DE538 reputedly uses the same chipset (maybe a different revision) only the chip on the card is not marked as such.
My plan is for the desktop pc to fire up every night and backup my dedicated server.
I used to be a Dlink fan but after the DI624 and this DE538 I would rather buy Belkin.

