thats a nice looking problem u have there.
what does it have to do with icmp i wonder? ...why would icmp affect file sharing in windows...? ...my guess it that it doesn't ...and then i wonder ... what else could it be? .. the first thing i'm thinking of is the cabling...u say that they are twisted pair cables ... uhm..
i'm not sure how signals go through all the 4/8 wires there ...but i'm sure u could have a signal mistake due to an wrong cripping of the cables ...so see if u connect the 2000 with the other win if they could see themself ... then switch cables.. ...i could try buying a 4 port hub if u don't want to spend more ... but the thing is that icmp shouldn't affect them too much .. anyway i will and u should read how is the file sharing connection made in windows ...check how do the computer check for life in network ...your linux station might not route something there ...but the cable problem should be checked also ...
wires go crazy sometimes ...like computers ..
thank you
--==CtrlAltDel==--