Alternate data locations ?

Hi:

I'm installing postgresql-7.0.2 from ftp.postgresql.org on a clean
redhat 6.2 system.

I'd like to create an alternate data location, similar to that supported
in pgsql 6.3, so,
I do:

$ export ARC_P_DAT_01="/home/httpd/data/arc_p_dat_01"
$ initlocation initlocation $ARC_P_DAT_01
<snip>
initlocation is complete
$ createdb -D $ARC_P_DAT_01 test
ERROR: The database path '/home/httpd/data/arc_p_dat_01' is invalid.
This may be due to a character that is not allowed or because the chosen
path isn't permitted for databases
createdb: database creation failed
$ sudo -u postgres ls -l $ARC_P_DAT_01
total 4
drwx------ 2 postgres http_adm 4096 Aug 18 23:10 base

So, everything looks okay. Can anyone give me a hint what might be
happening ? What can I do to debug this ?

Thanks,
-- Pat