Error restoring after 8.3 upgrade

We have a database that we're upgrading from 8.2 to 8.3. Our basic
prodecure is to make a backup of the data using pgAdmin, remove 8.2,
install 8.3, then use pgAdmin to restore the data. That works fine on
our test system, but on the actual server we get the following error
during the restore:

pg_restore: [archiver (db)] error returned by PQputCopyData: could not
send data to server: No buffer space available (0x00002747/10055)
pg_restore: *** aborted because of error

Our support staff says the server OS is Windows Server 2003, but they
don't have the other machine specs documented. I'm trying to get those
details.

Google turned up a few discussions of similar errors that may be
related, but no certain fixes:
http://archives.postgresql.org/pgsql-general/2006-01/msg00769.php
http://archives.postgresql.org/pgsql-bugs/2006-07/msg00051.php
http://archives.postgresql.org/pgsql-bugs/2006-04/msg00260.php
http://archives.postgresql.org/pgsql-general/2006-01/msg00328.php
http://www.webservertalk.com/archive307-2007-3-1832662.html
http://osdir.com/ml/db.postgresql.ports/2005-11/msg00000.html
http://www.mail-archive.com/pgsql-bugs(at)postgresql(dot)org/msg15449.html

We've tried adjusting the buffer sizes in postgresql.conf and the
Windows registry tweak that one site suggested, but neither of those
made any apparent difference.

Naturally I'm hoping this is a common, well-known issue with an easy
fix, but of course I don't expect that to be the case. :-)

Thanks,
Ryan