LONDON (Reuters) – A first edition of “Harry Potter and the Philosopher’s Stone”, with some errors and signed by author J.K. Rowling, is going up for a private sale at Christie’s in London, with the auction house inviting offers starting from 200,000 pounds ($250,000). The publication is one of 500 hardback copies of the book that were printed in an initial run in 1997. Three hundred of those were sent to libraries. The one being sold by Christie’s, as part of its upcoming “The Art of Literature: Loan and Selling Exhibition”, is among the other 200. “There were a few things that they seemed to…