connecting to MS access with php when defined password for database

I am trying to connect Ms Access DataBase from php . My codes like this in config.php

 define('DBNAMEACCESS',  '\\'."\\xxx.xxx.xxx.xxx\\test\\test.accdb");
        define('DBACCESSPASSWORD', 'mypassword');
        define('DBACCESSUSERNAME', '');

and in process.php like this:

     include './config.php';
   if (!file_exists(DBNAMEACCESS)) {
            die("Could not find database file.");
        }
 try{
            $dbName=DBNAMEACCESS;
            $username=DBACCESSUSERNAME;
            $password=DBACCESSPASSWORD;
             $dba = odbc_connect("Driver={Microsoft Access Driver (*.mdb, *.accdb)};Dbq=$dbName",$username, $password);

   if ($dba) {
/*......*/
} else
            {
                die("Could not connect to access database");
            }
             }
        catch (Exception $ex) {
//            var_export($ex);
                setmessage($ex) ;
        }

when the password is defined for access file , I get this error on this line: My error: odbc_connect(): SQL error: [Microsoft][ODBC Microsoft Access Driver] Cannot open database '(unknown)'. It may not be a database that your application recognizes, or the file may be corrupt., SQL state S1000 in SQLConnect in this line

         $dba = odbc_connect("Driver={Microsoft Access Driver (*.mdb, *.accdb)};Dbq=$dbName",$username, $password);

and when the password is not defined for access file,My codes execute correctly.