There they were hitting the hardwoods again Monday night. Not those college hoopsters in the NCAA's "Big Dance," but the 11 latest celebrity entrants on ABC's Dancing with the Stars. Marquee player Heather Mills, charitably billed as a "charity campaigner" in the two-hour opener, of course had to wait until near last to show whether she could make it through the fox trot with an artificial left limb. She nimbly did so. Not cheering her on: Paul McCartney. Their mega-nasty divorce proceedings in merry olde England have cut into some of Mills' practice time with pro partner Jonathan Roberts.