3COM Megahertz LAN 10/100
Model: 3CXFE574BT
As far as I know, that card is not capable of being supported on Amiga. (I think all 3COM Megahertz models are actually Cardbus cards.)
The only 3Com ones that work are the older Etherlink III style cards (most common is the 3C589.)
The Amiga is only capable of using original PCMCIA devices, and there is no "generic" PCMCIA network driver, as each card family is implemented slightly differently.
The only two families that are supported are:
3c589 (Etherlink III chipset) (through 3c589.device)
generic NE2000 chipset (through cnet.device)
With a little searching at the local swap, you should be able to find one of these cards for $5-$15, though. I have a 3c589 sitting here looking at me, but I haven't had a chance to copy over Miami and try to get it installed properly. (In fact, up until a couple weeks ago, I had no idea where I saved my Miami keyfile... Which is seriously a problem, since you can't confirm old ones, or even buy new ones, anymore. :-( )