Does anybody uses successfully SP Commerce with Paymill SP?

I get this error when I add a new subscription product:

Notice: Undefined index: period in commerce_sp_paymill_convert_interval_field() (line 711 of /home/nginx/domains/mydomain.com/public/sites/all/modules/commerce_sp_paymill/commerce_sp_paymill.module).
Notice: Undefined index: interval in commerce_sp_paymill_convert_interval_field() (line 712 of /home/nginx/domains/mydomain.com/public/sites/all/modules/commerce_sp_paymill/commerce_sp_paymill.module).