After updating eShop from 6.3.5 to 6.3.7 on WP v3.5, I began receiving errors in the dashboard as follows:
Warning: call_user_func_array() [function.call-user-func-array]: First argument is expected to be a valid callback, 'eshop_orderhandle_process' was given in /*path-to-wp-install*/wp-includes/plugin.php on line 487.
Rolling back to 6.3.5, the warning disappears. Only other plugins activated are Akismet and Google Analytics.
Site is http://beccayoderart.com. Errors won't appear because I'm back on eShop v6.3.5, and they're only showing to logged-in admin users.
Others are apparently having the same issue: