I'm writing a series of wrapper functions in Perl for some stored procedures in an Oracle 10 database. I'm using essentially the same code to retrieve the return values of two different procedures, and it works for one (returning an integer) but not the other (returning undef). I've called the PL/SQL code directly in the database and it behaves as expected; assuming that the problem is not in the database, what might cause this problem?

sub Create($$$) {
    my $dbh = shift(@_);         
    my @parameters = @_;        
    my $return_value;
    
    eval {

    my $func = $dbh->prepare(q{
        DECLARE
        returned_cursor foo_CURSOR;
        returned_row    foo_view%ROWTYPE;  
        BEGIN
            returned_cursor := foo.fn(
            :parameter1,
            );
        FETCH returned_cursor INTO returned_row;
        :id := returned_row.id;
        END;
    });
    $func->bind_param(":parameter1", $parameters[1]);
    $func->bind_param_inout(":id", \$return_value, 1);
    $func->execute;    
    };
<error catching>
}
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Basically it calls the stored procedure fn in the schema foo, which creates a row in foo, and returns a cursor to a row in foo_view. I then want to return the id from this row. $return_value is undef for one use of this block, but the correct if for another.