我的PHP fopen（）无法读取最后一行？

I have an account system that reads info from a file. These include (in order) username, password, email, bio, reputation. But for some reason (when I load the data with a series of fgets()) It returns the following error:

Warning: fgets() expects parameter 1 to be resource, null given in /home/dsgamesr/public_html/lualessons.x10host.com/userpage.php on line 95.

I made sure that $rep was an item in the text file. The program proceeds but still resets the $rep variable (and saves it as) blank. The code is as follows:

<?php 

    if (isset($_POST['button1'])) 
    {
        $file=fopen("Users/user".$_SESSION['Username'].".txt","r");
        $user=trim(fgets($file));
        $pass=trim(fgets($file));
        $email=trim(fgets($file));
        $bio=trim(fgets($file));
        $rep=fgets($files);

        fclose($file);
        echo $rep;

        $nfile=fopen("Users/user".$user.".txt","w");
        fwrite($nfile,$user."
");
        fwrite($nfile,$pass."
");
        fwrite($nfile,$email."
");
        fwrite($nfile,$_POST['bio']."
");
        fwrite($nfile,$rep."
");
        echo'Bio succesfully updated';
        //echo $user;

    }

?>

There is a total of five lines before I submit the new bio and a total of 5 with the final line blank after I submit it.