[Mailman-Users] strange problem with rebuilding archives, mailman thinks it's in a different directory

[arif]

I'm hoping someone can help me with this.  I'm getting this error when
using arch to rebuild an archive, what's odd is the line that seems to
be looking for an archive mbox in /usr/share, even though mailman is
configured and installed in /var/mailman.  Here's the error message from
the arch command:
 ./arch ny-oc /var/mailman/archives/private/ny-oc.mbox/ny-oc.mbox  
Traceback (innermost last):
  File "./arch", line 129, in ?
    main()
  File "./arch", line 116, in main
    archiver = HyperArchive(mlist)
  File "/var/mailman/Mailman/Archiver/HyperArch.py", line 578, in
__init__
    self.__super_init(dir, reload=1, database=db)
  File "/var/mailman/Mailman/Archiver/pipermail.py", line 269, in
__init__
    mkdir(self.basedir, self.DIRMODE)
  File "/var/mailman/Mailman/Utils.py", line 559, in mkdir
    os.mkdir(dir, mode)
OSError: [Errno 2] No such file or directory:
'/usr/share/mailman/archives/private/ny-oc'

can anyone tell me how I can fix this?
thanks much,
-arif