Pianist Rudolf Buchbinder has performed with the world's greatest orchestras and has released more than 100 recordings. As a five-year-old, more than 55 years ago, he became the youngest student to enter the Vienna Musik Hochschule. Yet he still struggles with stage fright. This past weekend Buchbinder performed Brahms' Piano Concerto No. 1 with the Minnesota Orchestra and, at the piano, spoke with Brian Newhouse about the piece and his bad case of freezing fingers.