1. Comment out the line: 

   print "Content-type: text/html\n\n"; 

2. Find this: 
   &require_supporting_libraries (__FILE__, __LINE__, 
                    "./Library/web_store.setup.frames.javascript"); 
                    # "./Library/web_store.setup.html"); 
   
and add this right under it: 
                    
   &require_supporting_libraries (__FILE__, __LINE__, 
                    "./Library/cookie.lib"); 

Make sure you put the cookie.lib file available from
Matt  Wright (http://www.worldwidemart.com/scripts/)in
your Library directory. 

3. Then find this: 

   if ($cart_id eq "") 
                    { 
                    &delete_old_carts; 
                    &assign_a_unique_shopping_cart_id; 
                    } 

And replace it with this: 
                    
   if ($form_data{'cart_id'} eq "") { 
                    &GetCookies; 
                    if ($Cookies{'cart_id'} ne "") { 
                    $cart_id = $Cookies{'cart_id'}; 
                    } 
                    else { 
                    &delete_old_carts; 
                    &assign_a_unique_shopping_cart_id; 
                    &SetCookies('cart_id',"$cart_id"); 
                    } 
                    } 
                    else { 
                    if ($form_data{'order_form_button'} ne "") { 
                    &SetCookies('cart_id',""); 
                    } 
                    $cart_id = $form_data{'cart_id'}; 
                    } 

                    print "Content-type: text/html\n\n"; 

(I'll paste that section again with the commenting
intact, I'm not  sure if it will look right as it looks horrible in
this text area.) 

if ($form_data{'cart_id'} eq "") { #Have a cart_id?? 
                    &GetCookies; #Get cookies 
                    if ($Cookies{'cart_id'} ne "") { #Valid cart_id cookie ?? 
                    $cart_id = $Cookies{'cart_id'}; #Set cart_id as the cookie 
                    } 
                    else { #No cart and no cookie 
                    &delete_old_carts; #Delete old carts 
                    &assign_a_unique_shopping_cart_id; #Get new cart 
                    &SetCookies('cart_id',"$cart_id"); #Set cookie as the cart_id 
                    } 
                    } 
                    else { #Already have a cart_id 
                    if ($form_data{'order_form_button'} ne "") { #Going to
                    checkout 
                    &SetCookies('cart_id',""); #Clear the cart_id cookie 
                    } 
                    $cart_id = $form_data{'cart_id'}; #Still shopping 
                    } 

                    print "Content-type: text/html\n\n"; #Content header