Actually, I've been having this problem as well.  I'm using an Apple
Ethernet card with 16k cache.  Net traffic on the wire that the Mac IIci
is attached is always high though. There are about ~140 machines in that
subnet all doing all kinds of traffic. Most in the ~40MHz and up
catagory spewing packets onto the wire.  Go figure,  8-)

But I must say that as far as I can tell this warning seems harmless enough.  
NetBSD keeps rolling along reguardless.

Ian