os.walk help

[hokieghal99]

This script is not recursive... in order to make it recursive, I have to 
call it several times (my kludge... hey, it works). I thought os.walk's 
sole purpose was to recursively walk a directory structure, no? Also,it 
generates the below error during the os.renames section, but the odd 
thing is that it actually renames the files before saying it can't find 
them. Any ideas are welcomed. If I'm doing something *really* wrong 
here, just let me know.

#-------------- ERROR Message ----------------------#

   File "/home/rbt/fix-names-1.1.py", line 29, in ?
     clean_names(setpath)
   File "/home/rbt/fix-names-1.1.py", line 27, in clean_names
     os.renames(oldpath, newpath)
   File "/usr/local/lib/python2.3/os.py", line 196, in renames
     rename(old, new)
OSError: [Errno 2] No such file or directory

#------------- Code -------------------------#

setpath = raw_input("Path to the Directory: ")
bad = re.compile(r'[*?<>/\|\\]')
for root, dirs, files in os.walk(setpath):
    for dname in dirs:
       badchars = bad.findall(dname)
       for badchar in badchars:
          newdname = dname.replace(badchar,'-')
          if newdname != dname:
             newpath = os.path.join(root, newdname)
             oldpath = os.path.join(root, dname)
             os.renames(oldpath, newpath)