Simple CREATE TABLE in DBI::Pg?

Here's the program, in Perl; I've pared it down to the bare minimum:

    #!/usr/local/bin/perl

    use DBI;

    sub tbl_easy_init {
        local( $dbh ) = shift;
        local( $sth ) = $dbh->prepare( "create table tbl_easy (id int4)" );
        $sth->execute();
    }

    $dbh = DBI->connect( "dbi:Pg:dbname=booga", "", "",
                 { "PrintError" => 0, "AutoCommit" => 0 } );

    $rv = &tbl_easy_init( $dbh );

This program fails.  I've tried it with all global variables, tried a number of
different CREATE TABLE statements, and so on, and $rv always winds up being
equal to -1.  Yet, typing in the CREATE TABLE statement in psql works.

If the table is already created in psql, I can use all manner of select
statements in the above program skeleton, and it'll work.

So.  What am I doing wrong?

                            ---Ken