hes not unable to... its a hard solo no matter how good you are, particularly the change between tapping and sweeping near the end; playing something in your bedroom on the thousandth try (which is what i do haha!) is one thing... playing something 100% perfect on stage in front of thousands of people, first time, once they've already been on stage for nearly an hour, headbanging away trying to interact with the fans... is another thing.
Besides Chris played it perfectly when i saw them XD