Problem with restoring database from 7.3.1 to 8.0.1

Hi Folks,

I have a small problem.  We're currently using an old PostgreSQL 7.3.1
database. In near future we want to migrate to a new server and taking
the chance to upgrade postgres. Now I have a testsystem with postgres
8.0.1 where I tried to import a dump from our database. Everthing works
fine except 74 error messages which all look simliar to this one:

pg_restore: [Archivierer (DB)] Fehler in Inhaltsverzeichniseintrag 639;
0 33230571 CONSTRAINT $3 mh1004
pg_restore: [Archivierer (DB)] could not execute query: FEHLER:
Relation »public.$3« existiert nicht
    Command was: ALTER INDEX public."$3" OWNER TO mh1004;

Sorry it's the german version. I think the translation could be:

pg_restore: [Archivierer (DB)] Error in index directory 639; 0 33230571
CONSTRAINT $3 mh1004
pg_restore: [Archivierer (DB)] could not execute query: Error:  relation
»public.$3« does not exist
    Command was: ALTER INDEX public."$3" OWNER TO mh1004;

mh1004 is the postgres user for this database. Everthing seems to work
fine but I would really like to know what this error does mean.

Thanks and *greets*
Kai