No it is not normal.
The fan which extracts the hot air from the dryer is driven by a belt connected to the drum. If the clothes are spinning and there is no air blowing our from the rear then I suspect that you have a broken belt. This should be fairly in expensive to buy and install your self. Just remove the plate on the back of the machine with a screw driver.
If the clothes are not spinning then you should buy a new machine which you may have considering the date of your post.
Hope this helps y'all
Hamish
June 2008