IPN: error - Subscription Error

The following error message was generated while trying to acknowledge IPN:

        Notification received was NOT from PayPal - Message was ignored. http://www.paypal.com/cgi-bin/webscr: INVALID

User Information

	Subscriber's Username: pp-moreljeep
	Subscriber's Email: klip(*)testcustomer.com
	Subscription Number: S-5U062985259837439
	Transaction Type: subscr_payment

Query:mc_gross=0.05&address_status=confirmed&payer_id=RP5LPT45BTH82&address_street=10%20Willy%20Han&payment_date=03%3A03%3A32%20Sep%2009%2C%202007%20PDT&payment_status=Completed&charset=windows-1252&address_zip=M4E%203X5&first_name=Klip&option_selection1=Using%20free%20mailers&mc_fee=0.05&address_country_code=CA&password=nh6tqkPzb61z.&address_name=Klip%20Rogers&notify_version=2.4&subscr_id=S-5U062985259837439&payer_status=verified&business=service%40testcompany.com&address_country=Canada&address_city=Toronto&verify_sign=AiKZhEEPLJjSIccz.2M.tbyW5YFwAsbxL4GZN7gsG3RhtxAy.cXd6sza&payer_email=klip%40testcustomer.com&username=pp-moreljeep&option_name1=I%20will%20send%20my%20CD%2FDVD%27s%20to%20Ar%2Akiv&txn_id=82T118712B216504B&payment_type=instant&last_name=Rogers&address_state=Ontario&receiver_email=service%40testcompany.com&payment_fee=&receiver_id=NVZBFVWF6XPEG&txn_type=subscr_payment&item_name=Arkiv%27s%20Monthly%20Membership%20Fee&mc_currency=CAD&item_number=100M&residence_co!  untry=CA&test_ipn=1&payment_gross= Received on Sun Sep 09 2007 - 06:04:04 EDT