Robert Redford has been forced to scrap plans to make a third film with old pal Paul Newman - because his BUTCH CASSIDY + THE SUNDANCE KID partner is serious about retiring. Newman, 82, announced his retirement in May (07), blaming memory loss and a lack of confidence for his decision, and the news shattered Redford's dreams of making a final film with the actor-turned-philanthropist. In an interview with Playboy magazine, Redford says, "It's (a new movie together) not happening, sadly. Paul and I were planning on doing a film version of Bill Bryson's wonderful book A Walk In The Woods. "I got the rights to it four years ago, and we couldn't decide if we were too old to do it. Then we decided, 'Let's go for it.' "But time passed, and Paul's been getting old fast. I think things deteriorated for him. Finally, two months ago he called and said, 'I gotta retire.' "The picture was written and everything. It breaks my heart."