DBD::Pg: Placeholders not working

Greetings-

Recently I upgraded to PostgreSQL 7.2.1, running under debian's
"woody" release. Since then, perl scripts using DBD::Pg and placeholders
aren't working. The equivalent SQL statements, sent through DBD::Pg, work
fine, so I know it's a problem with the placeholders.  I've upgraded to
the most recent DBD::Pg (1.13).

Here's the symptom:

my $put = $dbh->prepare('UPDATE letters SET sc_auth_sum = ?, ' .
    'sc_anti_auth_sum = ?, ' .
    'sc_pro_auth_sum = ?, sc_auth_valence = ? WHERE letterid = ' .
    '?');

...

I generate the hash %out, which contains:
  DB<2> x %out
0  'sc_auth_sum'
1  '-1'
2  'letterid'
3  73012
4  'sc_auth_valence'
5  7
6  'sc_anti_auth_sum'
7  4
8  'sc_pro_auth_sum'
9  3


and then do:
    $put->execute($out{sc_auth_sum}, $out{sc_anti_auth_sum},
          $out{sc_pro_auth_sum}, $out{sc_auth_valence},
          $out{sc_letterid});
    $dbh->commit;

so at this point the four columns (sc_auth_sum, sc_auth_valence,
sc_anti_auth_sum, and sc_pro_auth_sum) should be calculated. But:

auth=# select sc_auth_sum, sc_auth_valence, sc_anti_auth_sum,
sc_pro_auth_sum from letters where letterid=73012;
 sc_auth_sum | sc_auth_valence | sc_anti_auth_sum | sc_pro_auth_sum
-------------+-----------------+------------------+-----------------
             |                 |                  |
(1 row)

HOWEVER, if I do:
  DB<3> $dbh->do('UPDATE letters SET sc_auth_sum=-1, sc_auth_valence=7,
sc_anti_auth_sum=4, sc_pro_auth_sum=3 WHERE letterid=73012')

  DB<4> $dbh->commit


it works fine:
auth=# select sc_auth_sum, sc_auth_valence, sc_anti_auth_sum,
sc_pro_auth_sum from letters where letterid=73012;
 sc_auth_sum | sc_auth_valence | sc_anti_auth_sum | sc_pro_auth_sum
-------------+-----------------+------------------+-----------------
          -1 |               7 |                4 |               3
(1 row)


Any advice will be most welcome.


----------------------------------------------------------------------
Andrew J Perrin - http://www.unc.edu/~aperrin
Assistant Professor of Sociology, U of North Carolina, Chapel Hill
clists@perrin.socsci.unc.edu * andrew_perrin (at) unc.edu