Left Join fails with Unknown column in on clause - left-join

Question

I have two queries that run against the same table(s) except the second one fails with the addition of a Left Join.
Runs Successfully
SELECT *
FROM paypal_ipn_orders
LEFT join itemkey on paypal_ipn_orders.item_number = itemkey.item_id
WHERE packing_slip_printed = 0
AND LOWER(payment_status) = 'completed'
AND address_name <> ''
order by itemkey.sort_id;
Yet this second query Fails with "Unknown column 'paypal_ipn_orders.item_number' in 'on clause'", Yet it runs fine with out the left join. The Paypal_ipn_orders table does contain the item_number field.
SELECT *
FROM paypal_ipn_orders as table1,
(SELECT payer_email, COUNT(*) as count FROM paypal_ipn_orders GROUP BY payer_email ORDER BY count DESC) as table2
LEFT join itemkey on table1.item_number = itemkey.item_id
WHERE table1.payer_email = table2.payer_email
and packing_slip_printed = 0
AND LOWER(payment_status) = 'completed'
AND address_name <> ''
ORDER BY count DESC, auction_multi_item, item_number;
The comma after table1 is required as the (SELECT... is part of the FROM clause.
An interesting note. I changed the order of the From clause to:
SELECT *
FROM (SELECT payer_email, COUNT(*) as count FROM paypal_ipn_orders GROUP BY payer_email ORDER BY count DESC) as table1,
paypal_ipn_orders as table12
LEFT join itemkey on table2.item_number = itemkey.item_id
WHERE table2.payer_email = table1.payer_email
and packing_slip_printed = 0
AND LOWER(payment_status) = 'completed'
AND address_name <> ''
ORDER BY count DESC, auction_multi_item, item_number;
and now the error message is: Unknown column 'table2.payer_email' in 'where clause'. But this will not run with out the Left Join. Giving the same Unknown column in where clause message.
FYI - This works:
SELECT payer_email, COUNT(*) as count
FROM paypal_ipn_orders
WHERE packing_slip_printed = 0
AND LOWER(payment_status) = 'completed'
AND address_name <> ''
GROUP BY payer_email
ORDER BY count DESC;

Answer 1

FROM paypal_ipn_orders table1,
Do you mean... FROM paypal_ipn_orders AS table1 (...?
Also note that comma at the end of table1,. I'm not sure if that's intended?

Answer 2

This is what worked in the end:
SELECT *
FROM (SELECT payer_email, COUNT(*) as count
FROM paypal_ipn_orders
Where packing_slip_printed = 0
AND LOWER(payment_status) = 'completed'
AND address_name <> ''
GROUP BY payer_email
ORDER BY count DESC) as table1,
paypal_ipn_orders as table2
LEFT join itemkey on table2.item_number = itemkey.item_id
WHERE table1.payer_email = table2.payer_email
and packing_slip_printed = 0
AND LOWER(payment_status) = 'completed'
AND address_name <> ''
ORDER BY count DESC, auction_multi_item, sort_id