VACUUM WARNING: skipping

PostgreSQL 8.2.9 on i686-pc-linux-gnu, compiled by GCC gcc (GCC) 3.4.6 20060404 (Red Hat 3.4.6-9)
with autovacuum = on

I'm getting these warnings:

2009-08-12 10:36:24 EDT,5509339,VACUUM WARNING: skipping "sql_sizing_profiles" --- only table or database owner can vacuum it

for various information_schema and pg_catalog objects. For example:

sql_sizing
sql_features
sql_implementation_info
pg_database

I ran vacuum verbose by hand and it did seem to work on these guys:

INFO: vacuuming "pg_catalog.pg_database"
INFO: "pg_database": found 0 removable, 4 nonremovable row versions in 1 pages
DETAIL: 0 dead row versions cannot be removed yet.
Nonremovable row versions range from 128 to 176 bytes long.
There were 3 unused item pointers.
Total free space (including removable row versions) is 7536 bytes.
0 pages are or will become empty, including 0 at the end of the table.
1 pages containing 7536 free bytes are potential move destinations.
CPU 0.00s/0.00u sec elapsed 0.00 sec.

Suggested action?