Well it's because it is searching for both file or folder which are not the same.
If you really don't wish to code around this then I'd suggest this request be posted in the SUGGESTIONS forum where it could be more easily seen by Ruud
and possibly be incorporated into future versions.

In the meantime one could do some thing similar to this.

Code:

If GetFileAttr($Name) & 16
  ;folder exists
EndIf

 
 
 
There is also this UDF
 
EmptyFolder() - checks if folder is empty
http://www.kixtart.org/ubbthreads/showflat.php?Cat=0&Number=83104