[BusyBox] chmod problem

[Ben Weintraub]

Alright, so if I can't get tar to preserve permissions correctly, I
figured I could just go change the permissions on the files manually. 
However, chmod doesn't seem to work for me, using either numeric
permissions or the +/- format.  
Here is an example:
# ls -lh foo
-rwxr-xr-x    1 root     root       491.9k Jan  2 22:37 foo
# chmod a+w foo; ls -lh foo
-rwxr-xr-x    1 root     root       491.9k Jan  2 22:37 foo
# chmod a+s foo; ls -lh foo
-rwxr-xr-x    1 root     root       491.9k Jan  2 22:37 foo
# chmod 444 foo; ls -lh foo
----------    1 root     root       491.9k Jan  2 22:37 foo

And after the permissions go blank, I am unable to change them back to
anything workable.  I found one person who had this problem on another
mailing list, but nobody answered his question.  Am I doing something
wrong or is this a bug?  The version of busybox is 1.00-pre3, but I also
had the problem with 60.5 when I was using that.
Thanks,
Ben