Having trouble getting data_sources to work on OS X 10.5.6

When I run $dbh->data_sources() or DBI->data_sources('Pg') I get undef  
as a result.

Is there some way I can debug why this is happening easily (or at all).

So far I'm getting this from trace:

-> data_sources in DBD::_::db for DBD::Pg::db  
(Apache::DBI::db=HASH(0xe8a534)~0xe8a4bc) thr#900600
-> data_sources for DBD::Pg::dr (DBI::dr=HASH(0xe8896c)~INNER)  
thr#900600
DESTROY for DBI::db=HASH(0xe8a9b4) ignored - handle not initialised
!! ERROR: 1 'FATAL:  role "_www" does not exist' (err#0)
<- data_sources= ( undef ) [1 items] at DBI.pm line 1762
<- data_sources= ( undef ) [1 items] at Session.pm line 95

role seems to be the user/group of the apache process, but I'm trying  
to use the postgres user which is what I logged into with connect.

Any ideas?

Thanks,
Boysenberry Payne