Probably just an interrupt conflict
PCMCIA Installation and Configuration Issues
PCMCIA Problem with 3COM 3C562D/3C563D "eth0: interrupt(s) dropped" (John Auld)
Dropped interrupts (David Hinds)
Hardware & Software details (John Auld)
Date: 2000, Mar 20
From: David Hinds <email@example.com>
You probably just have an interrupt conflict with some other system
device. I'd start by excluding interrupts in /etc/pcmcia/config.opts
and see if that fixes the problem.
to: "Probably just an interrupt conflict"