I certainly haven't noticed a noise like that on mine - the zoom action is a smooth 'swish'.
EDIT: see this thread reporting the same issue (OP there returned the lens, got a silent replacement).
Thanks a lot! Man, that wasn't to reassuring though Luckily I'm doing a trip to where I ordered it from so I'll be sure to either replace it or be reassured. Hopefully swap one, and pray that it is otherwise as perfect as this one is optically.