Unsupported Operand Types In / - What this =?

<?php
session_start();

include "database.php";

############################################################


    function attack(){
#Line 10        
        #Ge $dbQueryHealth ett värde
        $atkuser= mysql_real_escape_string($_POST['atkuser']);
$querythe =("SELECT temphealth FROM characters WHERE user='$atkuser'")or die(mysql_error());    
        #Sätt $currentHealth med värdet från databas-resursen $dbQuery
        if(mysql_num_rows(mysql_query($querythe)) == 1)
    {
        $currentHealthEnemy = mysql_fetch_assoc(mysql_query($querythe));
        }else{ die("User Don't Excist. Please Go Back And Try Again");}
#Line 20                             
            

$nuser=mysql_real_escape_string($_SESSION['user']);
$auser=mysql_real_escape_string($_SESSION['admin']);

if($nuser){
$userfinal=$nuser;
}elseif($auser){
$userfinal=$auser;
#Line 30
}
        ####################################################
$querythy ="SELECT temphealth FROM characters WHERE user='$userfinal'"or die(mysql_error());

        
        #Sätt $currentHealth med värdet från databas-resursen $dbQuery
        $currentHealthYou = mysql_result(mysql_query($querythy),0)or die(mysql_error());  
#Line 40
  
        
       $minHealth = 0;
       $maxHealth = 100;
       $expAward = mt_rand (1, 300);
       $healthAward = mt_rand (1, 30);
       $winner= mt_rand (0, 1);


#Line 50
    if($winner) {
            if(($currentHealthEnemy - $healthAward) > $minHealth) {  
                $currentHealthEnemy -= $healthAward;
                #$currentExp + expAward;
                echo "You won! The enemy now have {$currentHealthEnemy} HP.";  




/*Line 60 */






            } else {


#Line 70              
  echo "You won! You Killed The Enemy";
                $currentHealthEnemy = $maxHealth;
                #$currentExp + expAward;
            }
        } else {
            if(($currentHealthYou - $healthAward) <= 0) {
                echo "You Lost. The Enemy killed you.";
                $currentHealthYou = 100;
            } else {
#Line 80        $currentHealthYou -= $healthAward;
                echo "You lost! You've lost {$healthAward} HP. You now have {$currentHealthYou} HP.";
            }  
        }

$nuser=mysql_real_escape_string($_SESSION['user']);
$auser=mysql_real_escape_string($_SESSION['admin']);

if($nuser){
#Line 90
$userfinal=$nuser;
}elseif($auser){
$userfinal=$auser;
}    
$SeUs = $userfinal;
$PoUS = mysql_real_escape_string($_POST['atkuser']);
$result = mysql_query("UPDATE characters SET temphealth='$currentHealthYou' WHERE user='$SeUs'")
or die(mysql_error());
#Line 100

$result = mysql_query("UPDATE characters SET temphealth='$currentHealthEnemy' WHERE user='$PoUS'")
or die(mysql_error());

        #mysql_query ("UPDATE characters SET exp = \"{$currentExp}\" WHERE user =".$_SESSION['user']."");  
    }
echo attack();
#Line 110
mysql_close();
?>
<form action="index.php" method="post">
<input type="submit" name="home" value="Back to home">

#Line 50
  if ( $winner ) {
    if ( ( $currentHealthEnemy - $healthAward ) > $minHealth ) {
      $currentHealthEnemy -= $healthAward;
      // $currentExp + expAward;
      echo 'You won! The enemy now have ' . $currentHealthEnemy . 'HP';

$currentHealthEnemy = $currentHealthEnemy - $healthAward;