ok, i solved it.
i repleced in payment gateway php script in function process_payment:
get_permalink(get_option(‘woocommerce_pay_page_id’);
on:
get_permalink(woocommerce_get_page_id(‘pay’ );
I think that problem is not connected with theme.
I use default theme ‘Twenty Twelve’ and problem is still.
I did test transaction with paypal payment gateway and everything was correct.
I have the same problem with another payment gateway after upgrade to 2.1.
I created example shop with default theme and error is still.
