Description:
------------
When trying to use a bound parameter with the bts search datablade it gives the string data right truncated error.

Reproduce code:
---------------
<?

#create table fh_trees(id serial, fht_name char(60) );
#insert into fh_trees(fht_name) values ('test record');
#CREATE INDEX idx_fht_fht_name ON fh_trees (fht_name  bts_char_ops) using bts in extdbs;

        putenv("INFORMIXDIR=/opt/informix");
        putenv("INFORMIXSERVER=servertcp");
        putenv("ODBCINI=/opt/informix/etc/odbc.ini");
        try {
                $dbh = new PDO("informix:DSN=fht", "informix_account", "password");
                $dbh->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
                $dbh->setAttribute(PDO::ATTR_CASE, PDO::CASE_LOWER);

        } catch (Exception $e) {
                echo "Failed: " . $e->getMessage();
        }

        $sqlline = "select id, fht_name from fh_trees
                where bts_contains(fht_name, :search , score # REAL)";
        $sth = $dbh->prepare($sqlline);
        $sa = "test";
        $sth->bindParam('search',$sa);
        $sth->execute();
        $row = $sth->fetch();
        print_r($row);



Expected result:
----------------
Array
(
    [id] => 5
    [0] => 5
    [fht_name] => Test Tree
    [1] => Test Tree
)


Actual result:
--------------
Fatal error: Uncaught exception 'PDOException' with message 'SQLSTATE[22001]: String data, right truncated: -11023 [Informix][Informix ODBC Driver]String data right truncation. (SQLExecute[-11023] at /usr/src/php-5.2.5/ext/pdo_informix/informix_statement.c:730)' in /web/test_case.php:28
Stack trace:
#0 /web/test_case.php(28): PDOStatement->execute()
#1 {main}
  thrown in /web/test_case.php on line 28