WooCommerce Cannot Complete Transactions After Upgrade to WordPress 3.5

We updated our website to WordPress 3.5 and since then people cannot complete transactions via PayPal. When users click on Place Order an error message is returned. This started only after we upgraded to WordPress 3.5. We are using WooCommerce 1.6.6.

Error Message:

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Warning: Missing argument 2 for wpdb::prepare() in /home/websav/public_html/wp-includes/wp-db.php on line 990
> {"result":"success","redirect":"https:\/\/www.paypal.com<http://www.paypal.com>\/webscr?cmd=_cart&business=rebecca%40web-savvy-marketing.com<http://40web-savvy-marketing.com>&no_note=1¤cy_code=USD&charset=UTF-8&rm=1&upload=1&return=http%3A%2F%2Fwww.web-savvy-marketing.com<http://2Fwww.web-savvy-marketing.com>%2Fcheckout%2Fthank-you%2F%3Forder%3D5030%26key%3Dorder_50ddef9ea7bee%26utm_nooverride%3D1&cancel_return=http%3A%2F%2Fwww.web-savvy-marketing.com<http://2Fwww.web-savvy-marketing.com>%2F%3Forder_id%3D5030%26order%3Dorder_50ddef9ea7bee%26cancel_order%3Dtrue%26_n%3De9205bc16c&page_style=&invoice=WC-5030&custom=order_50ddef9ea7bee¬ify_url=http%3A%2F%2Fwww.web-savvy-marketing.com<http://2Fwww.web-savvy-marketing.com>%2F%3FpaypalListener%3Dpaypal_standard_IPN&first_name=Chris&last_name=Cree&company=SuccessCREEations%2C+Inc.&address1=4620+Spring+Canyon+Heights&address2=%23201&city=Colorado+Springs&state=CO&zip=80907&country=US&email=payments%40successcreeations.com<http://40successcreeations.com>&night_phone_a=912&night_phone_b=373&night_phone_c=6776&day_phone_a=912&day_phone_b=373&day_phone_c=6776&no_shipping=1&tax_cart=0.00&item_name_1=Christian%3A+Church+WordPress+Theme&quantity_1=1&amount_1=49.95"}

I am receiving emails from potential buyers giving me similar messages and everyone is asking why they can’t complete transactions.

Please help as this has a had a huge effect on revenue.

http://wordpress.org/extend/plugins/woocommerce/