As an addendum to my prior post:
After trying EPC with Windows 2000 and IE 7, I tried it under Linux (SuSE 10.1) with Firefox 2.0, and it worked like a champ. I suspect that the only critical issue is having a modern browser with the correct Java runtime version. (Vista doesn't ship with Java installed, which is probably why they say "use at your own risk".) I imagine that a Mac would work fine, too (though perhaps with Firefox rather than Safari).
-David Pease
'66 French 230SL