I do all of Cathe's workouts on carpet and have no problem. If you have particularly plush carpet a few of the pivot moves may be a little more difficult but it's so easy to modify it isnt really an issue.
I worked out on carpet until a year ago when we put down new carpet. My husband then bought me puzzle mats to put over the carpet so I wouldn't ruin it! Anyway, until the mats, it was never a problem working out on carpet!
Hello PateT and WELCOME
I am like Jo I used to do my workouts on carpet (berber) had no problems and than I got the puzzle mats and really like them! (make it easier on the knees ;-) )