Copyright and License question...

["Christian Edward Gruber" <cgruber@israfil.net>]

I've ported LambdaMOO, for a project I'm working on.  It's a MUD server.
Several core databases are provided under BSD-like licenses, but the
server's code has this or similar license prepended in comments to all
source files.  It seems to be sufficiently open, but I just don't know.
Of considerable concern may be the requirement to comply with export
control laws of the united states.  However, that may be implicit in law
anyway, and this notice might just be stating it explicitly, in which
case it's no different.  Any ideas?  Particularly, I'm wanting to know
what the PERMIT_* bits should be on it.  Also, the bit about sending
your name etc. is phrased as a request.  How binding is that legally?
Is it essentially a postcard-ware clause that's not a restriction, or
does it have any real implications?

Here's the copyright notice:

  Copyright (c) 1992, 1995, 1996 Xerox Corporation.  All rights
reserved.
  Portions of this code were written by Stephen White, aka ghond.
  Use and copying of this software and preparation of derivative works
based
  upon this software are permitted.  Any distribution of this software
or
  derivative works must comply with all applicable United States export
  control laws.  This software is made available AS IS, and Xerox
Corporation
  makes no warranty about the software, its performance or its
conformity to
  any specification.  Any person obtaining a copy of this software is
requested
  to send their name and post office or electronic mail address to:
   Pavel Curtis
   Xerox PARC
   3333 Coyote Hill Rd.
   Palo Alto, CA 94304
   Pavel@Xerox.Com