my $sql = <<'END';
select the_data
from my_table
where filter1 = ?
and filter2 = ?
END

# dbh is my database handle, already connected here
my $sth = $dbh->prepare($sql);

$sth->execute( $bind_val_1, $bind_val_2 );

# this line throws my error
my $data = $sth->fetchall_arrayref;

##</code><code>##

my $sql = <<'END';
select the_data
from my_table
where filter1 = $bind_val_1
and filter2 = $bind_val_2
END

# dbh is my database handle, already connected here
my $sth = $dbh->prepare($sql);

$sth->execute;

# This line now completes successfully
my $data = $sth->fetchall_arrayref;