You need to access column by index :

    if ( $nt = mysql_fetch_array($q)){
    echo $nt[0];
    }

(Note `if` instead of `while` - it's not required, but your query returns at most 1 row, so no need for `while`).  
If you want to access column by name, change the query to use aliases:

    $q=mysql_query(" SELECT COUNT (*) AS total_number FROM menjava 
    WHERE date_submitted >= DATE_SUB(CURRENT_DATE(), INTERVAL 1 DAY)",$link2);
    // now you can 
    if ( $nt = mysql_fetch_array($q)){
    echo $nt["total_number"];
    }

Also, while debugging it makes sense to output errors if any :

    $q=mysql_query(....) or die(mysql_error());