diff --git a/core/purchasing/includes/db/grn_db.inc b/core/purchasing/includes/db/grn_db.inc
index d2fbd7f..0820fb3 100644
--- a/core/purchasing/includes/db/grn_db.inc
+++ b/core/purchasing/includes/db/grn_db.inc
@@ -17,15 +17,14 @@ function update_average_material_cost($supplier, $stock_id, $price, $qty, $date,
        // save a couple of db calls like get_supplier()
        
        $supp = get_supplier($supplier);
-       if ($supplier != null)
+       if ($supplier != null) {
                $currency = $supp['curr_code'];
-       else
+        if ($supp['tax_included'])
+            $price = get_tax_free_price_for_item($stock_id, $price, $supp['tax_group_id'],
+                $supp['tax_included']);
+    } else
                $currency = null;
 
-       if ($supp['tax_included'])
-               $price = get_tax_free_price_for_item($stock_id, $price, $supp['tax_group_id'],
-                       $supp['tax_included']);
-
        if ($currency != null)
        {
                $ex_rate = get_exchange_rate_to_home_currency($currency, $date);

--- a/core/gl/gl_journal.php
+++ b/core/gl/gl_journal.php
@@ -149,7 +149,7 @@ function create_cart($type=0, $trans_no=0)
         {
             $net_sum = 0;
             foreach($cart->gl_items as $gl)
-                if (!is_tax_account($gl->code_id) && !is_subledger_account($gl->code_id, $gl->person_id))
+                if (!is_tax_account($gl->code_id) && !is_subledger_account($gl->code_id))
                     $net_sum += $gl->amount;
 
             $ex_net = abs($net_sum) - array_sum($tax_info['net_amount']);
diff --git a/core/gl/includes/db/gl_db_accounts.inc b/core/gl/includes/db/gl_db_accounts.inc
index 53eb5a9..dc60c13 100644
--- a/core/gl/includes/db/gl_db_accounts.inc
+++ b/core/gl/includes/db/gl_db_accounts.inc
@@ -224,7 +224,7 @@ function is_subledger_account($account)
 
     $result = db_query($sql,"Couldn't test AR/AP account");
     $myrow = db_fetch_row($result);
-    return $myrow[0];
+    return $myrow == false ? 0 : $myrow[0];
 }
 
 function get_subaccount_data($code_id, $person_id)
diff --git a/core/includes/references.inc b/core/includes/references.inc
index a928c7e..027aafd 100644
--- a/core/includes/references.inc
+++ b/core/includes/references.inc
@@ -227,7 +227,7 @@ class references
             return false;
 
         $result = db_fetch_row($result);
-        return $result[0];
+        return $result == false ? false : $result[0];
     }
 
     function is_new_reference($ref, $type, $trans_no=0)
diff --git a/core/includes/ui/items_cart.inc b/core/includes/ui/items_cart.inc
index 2fe92da..3c91f0b 100644
--- a/core/includes/ui/items_cart.inc
+++ b/core/includes/ui/items_cart.inc
@@ -144,8 +144,8 @@ class items_cart
         $this->gl_items[$index]->code_id = $code_id;
         $this->gl_items[$index]->person_id = $person_id;
 
-        $gl_type = is_subledger_account($code_id, $person_id);
-        if ($gl_type)
+        $gl_type = is_subledger_account($code_id);
+        if ($person_id != null && $gl_type)
         {
             $this->gl_items[$index]->person_type_id = $gl_type > 0 ? PT_CUSTOMER : PT_SUPPLIER;
             $data = get_subaccount_data($code_id, $person_id);
@@ -263,7 +263,7 @@ class items_cart
 
         foreach($this->gl_items as $gl)
         {
-            if ($person_type = is_subledger_account($gl->code_id, $gl->person_id))
+            if ($person_type = is_subledger_account($gl->code_id))
             {
                 $tax_info['person_type'] = $person_type < 0 ? PT_SUPPLIER : PT_CUSTOMER;
                 $tax_info['person_id'] = $gl->person_id;
@@ -520,8 +520,8 @@ class gl_item
 
         $this->code_id = $code_id;
         $this->person_id = $person_id;
-        $gl_type = is_subledger_account($code_id, $person_id);
-        if ($gl_type)
+        $gl_type = is_subledger_account($code_id);
+        if ($person_id != null  && $gl_type)
         {
             $this->person_type_id = $gl_type > 0 ? PT_CUSTOMER : PT_SUPPLIER;
             $data = get_subaccount_data($code_id, $person_id);
diff --git a/core/sales/includes/db/sales_order_db.inc b/core/sales/includes/db/sales_order_db.inc
index fcc19fd..17952e3 100644
--- a/core/sales/includes/db/sales_order_db.inc
+++ b/core/sales/includes/db/sales_order_db.inc
@@ -648,5 +648,5 @@ function last_sales_order_detail($order, $field)
 
         $last_query=db_query($sql, "Could not retrieve last order detail");
         $row = db_fetch_row($last_query);
-        return $row[0];
+        return $row == false ? false : $row[0];
 }
diff --git a/core/sales/includes/sales_db.inc b/core/sales/includes/sales_db.inc
index 6ff05f1..02cbaaf 100644
--- a/core/sales/includes/sales_db.inc
+++ b/core/sales/includes/sales_db.inc
@@ -231,6 +231,7 @@ function read_sales_trans($doc_type, $trans_no, &$cart)
     } else {
         // read header data from first document
         $myrow = get_customer_trans($trans_no[0],$doc_type);
+        $debtor_no = $myrow['debtor_no'];
         if (count_array($trans_no)>1)
             $cart->trans_no = get_customer_trans_version($doc_type, $trans_no);
         else
@@ -238,7 +239,7 @@ function read_sales_trans($doc_type, $trans_no, &$cart)
 
         $cart->set_sales_type($myrow["tpe"], $myrow["sales_type"], $myrow["tax_included"],0);
 
-        $cart->set_customer($myrow["debtor_no"], $myrow["DebtorName"],
+        $cart->set_customer($debtor_no, $myrow["DebtorName"],
             $myrow["curr_code"], $myrow["discount"], $myrow["payment_terms"]);
 
         $cart->set_branch($myrow["branch_code"], $myrow["tax_group_id"],
@@ -279,7 +280,7 @@ function read_sales_trans($doc_type, $trans_no, &$cart)
                     @$myrow["src_id"]);
             }
         }
-        $cart->prepayments = get_payments_for($trans_no, $doc_type, $myrow["debtor_no"]);
+        $cart->prepayments = get_payments_for($trans_no, $doc_type, $debtor_no);
 
     } // !newdoc
 
diff --git a/core/sales/includes/ui/sales_order_ui.inc b/core/sales/includes/ui/sales_order_ui.inc
index babf8f2..7172dff 100644
--- a/core/sales/includes/ui/sales_order_ui.inc
+++ b/core/sales/includes/ui/sales_order_ui.inc
@@ -400,7 +400,7 @@ function display_order_header(&$order, $editable, $date_text)
     if (($order->pos['cash_sale'] || $order->pos['credit_sale']) 
         && !$order->is_started()) {
          // editable payment type 
-        if (get_post('payment') !== $order->payment) {
+        if (isset($_POST['payment']) && $_POST['payment'] !== $order->payment) {
             $order->payment = get_post('payment');
             $order->payment_terms = get_payment_terms($order->payment);
             $order->due_date = get_invoice_duedate($order->payment, $order->document_date);

Function get_magic_quotes_gpc() is deprecated in file: C:\wamp3\www\account24\includes\session.inc at line 315

implode(): Passing glue string after array is deprecated. Swap the parameters in file: C:\wamp3\www\account24\includes\ui\ui_lists.inc at line 161

Trying to access array offset on value of type null in file: C:\wamp3\www\account24\reporting\includes\tcpdf.php at line 1127

chr() expects parameter 1 to be int, string given in file: C:\wamp3\www\account24\reporting\includes\tcpdf.php at line 3525