You have my sympathies about the XSurf killing a 4000. I had one go bad in mine, too. :-( Fortunatly, mine didn't cause any permanent harm to the 4000, though.
I picked up one of the ancient C= 2065 cards for cheap. As crazy as it sounds, it runs circles around what the XSurf could do in speed, and it's rock solid. (Albeit runs a bit hot, though... A small heat sink and a little re-routed fan air took care of that, though... I'm paranoid about conditions for my old 4000, now... it's seriously pampered)
But, honestly, I've heard good things about the VillageTronic network card, and even the old 2065 works for me... I know it's a bum deal to have to buy a used card for almost the price of a new one... But, to me, it seems like there is a reason the older cards hold their value........
If swapping the cards to different slots doesn't work, I'd probably fix the problem by avoiding the XSurf for a different card.