drop tablespace error: invalid argument

hello hackers,

i have problems dropping an existing empty tablespace. here is a
reduced example:

AscheMobil:~ asche$ cat test2.sql
CREATE TABLESPACE testspace LOCATION '/opt/postgresql/data2';
CREATE SCHEMA testschema;
CREATE TABLE testschema.foobar (id int) TABLESPACE testspace;
DROP SCHEMA testschema CASCADE;
DROP TABLESPACE testspace;

AscheMobil:~ asche$ /opt/postgresql/bin/psql asche <test2.sql
CREATE TABLESPACE
CREATE SCHEMA
CREATE TABLE
NOTICE: drop cascades to table testschema.foobar
DROP SCHEMA
ERROR: could not read directory "pg_tblspc/16464": Invalid argument
STATEMENT: DROP TABLESPACE testspace;
ERROR: could not read directory "pg_tblspc/16464": Invalid argument

AscheMobil:~ asche$ ls -l /opt/postgresql/data/pg_tblspc/
total 8
lrwx------ 1 asche staff 21 Aug 16 13:08 16464 -> /opt/postgresql/
data2

AscheMobil:~ asche$ ls -l /opt/postgresql/data2/
total 8
-rw------- 1 asche staff 4 Aug 16 13:08 PG_VERSION

AscheMobil:~ asche$ id
uid=501(asche) gid=20(staff) groups=20(staff),204(_developer),100
(_lpoperator),98(_lpadmin),81(_appserveradm),80(admin),79
(_appserverusr),61(localaccounts),12(everyone),402
(com.apple.sharepoint.group.1),401(com.apple.access_screensharing)

if i dont create the table testschema.foobar i can drop the tablespace
without problems. there is another effect i wonder about. when i
execute 'DROP TABLESPACE testspace;' two times at the end of script
the second drop statement drops the tablespace correctly.

AscheMobil:~ asche$ echo 'DROP TABLESPACE testspace;'>>test2.sql
AscheMobil:~ asche$ cat test2.sql
CREATE TABLESPACE testspace LOCATION '/opt/postgresql/data2';
CREATE SCHEMA testschema;
CREATE TABLE testschema.foobar (id int) TABLESPACE testspace;
DROP SCHEMA testschema CASCADE;
DROP TABLESPACE testspace;
DROP TABLESPACE testspace;

AscheMobil:~ asche$ /opt/postgresql/bin/psql asche < test2.sql
CREATE TABLESPACE
CREATE SCHEMA
CREATE TABLE
NOTICE: drop cascades to table testschema.foobar
DROP SCHEMA
ERROR: could not read directory "pg_tblspc/16469": Invalid argument
STATEMENT: DROP TABLESPACE testspace;
ERROR: could not read directory "pg_tblspc/16469": Invalid argument
DROP TABLESPACE

AscheMobil:~ asche$ ls -l /opt/postgresql/data2/
AscheMobil:~ asche$ ls -l /opt/postgresql/data/pg_tblspc/

AscheMobil:~ asche$ /opt/postgresql/bin/psql asche -c 'select version()'
version
----------------------------------------------------------------------------------------------------------------------------------------
PostgreSQL 8.4.0 on i386-apple-darwin10.0.0, compiled by GCC i686-
apple-darwin10-gcc-4.2.1 (GCC) 4.2.1 (Apple Inc. build 5646), 64-bit
(1 row)

this is the original postgresql-8.4.0 source package from http://www.postgresql.org/ftp/source/v8.4.0/
compiled with:
./configure --enable-debug --with-openssl --with-perl --with-python --
with-tcl --with-libxml --with-libxslt --with-zlib --prefix=/opt/
postgresql

it would be nice if somebody can take a look at this.

regards, jan otto