\lo_unlink results in "ERROR: pg_description: Permission denied."

After I've imported a huge file (1.3 GB) with "\lo_import", listed it with
"\lo_list" and tried to delete it with "\lo_unlink", I get the error:
"ERROR:  pg_description: Permission denied.".

I couldn't find anything in the documentation about large objects and their
expected behaviour, but I expected the lo to be deleted instead of this
error. The version of postgresql I use:
PostgreSQL 7.1 on i686-pc-linux-gnu, compiled by GCC 2.95.4

It is installed using the debian installation package postgres (
7.1release-4). Only I changed the data-directory (copied all files to
/home/postgres and created a softlink from /var/lib/postgres to
/home/postgres, while postgresql was not running.)

For me this was only a testdatabase, so for me it is not an urgent problem,
but I hope this can be solved.

Steven.

----------------------------------------
Steven Mooij
Kavezet Automatisering
Korvezeestraat 37
2628DB Delft

Telefoon:    +31 6 44960226
Email:        steven.mooij@kavezet.com
ICQ:        63799400