pg_dumpall -g problem

I have a Postgresql 7.2.2 installation, and I am having a problem with
the results of doing a pg_dumpall -g.

It dumps out three users, ignoring the fourth. If I connect to template1
with psql and do select * from pg_users I get four, and actually this fourth
is the one who owns all the user DBs, so I know it exists. It does dump
the postgres ID.

I also have a 7.3.2 system and that reports all except the postgres ID but
including the one that the 7.2.2 system ignores. Ignoring the postgres ID
makes some sense in that when you install Postgresql it gets set up by
default so it will be there anyway.

The missing one has a user ID of 101 if that is of any significance.

Is this a known problem? Is there a workaround?

Thanks in advance

David