You may have rolled it too thin. I have that problem sometimes and I think that's usually what causes it for me.
We're not the only ones who ever have fondant pucker Have you noticed that a lot of fondant cakes have a ribbon around the base, or a border of rolled balls? Sometimes that's just because it's the style...but I have a feeling the style was created to hide the pucker You probably could have arranged the drapes on the top to cover any puckers.
By the way, that's a pretty cake, very nice design. You did a great job of photographing it too.
alot of times the puckering is from rushing to get the fondant on to the cake, yes its harder to smooth on a thinner piece of fondant and it will happen more with that, Also, when smoothing the fondant on to the cake you need to ease the fondant down the side of the cake and not pull it.
And of course when all else fails as was stated already hide it!!
When I first started I didn't know how to get rid of the puckers either. After watching these two videos I now know how to avoid it. Watch how these decorators sort of fluff and smooth, fluff and smooth the fondant as they smooth the sides. By pulling the icing out away from the cake and smoothing it down you avoid these puckers.
Thanks so much for your replies and your suggestions!! The videos will be a great help and I'll try the techniques as I have to do another fondant cake next week.
Also, I always take my cake with cake board cut to the cake size and stack it on something (crisco can, etc.) so the fondant doesn't rest on anything but hangs. Then I fluff and smooth, fluff and smooth. Once I started fluffing my fondant looked so much better! Once smooth, take a knife or scissors and snip off the excess fondant.