yaya: Hi Neil, you are right and wrong. R2 to begin is definetely wrong, but the answer of the system too, because the result is a Ko. The system has not to play O1 but can fight the Ko. The right answer after R2 is just Q1 (Second Variation in .sgf) and White is dead. The right move is R1 to begin (first variation in .sgf) after that White lives.
Thank you guys for your help understanding the problem. I deleted my comment since it is incorrect.