RMDIR--Notes

Cannot delete directory with hidden or system files

You cannot delete a directory that contains files, including hidden or      
system files. If you attempt to do so, MS-DOS displays the following
message:

    Invalid path, not directory,
    or directory not empty

Use the <DIR>  command to list hidden and system files and the <ATTRIB>
command to remove hidden and system attributes from files. For more
information, see those commands.

Using the backslash character with the path parameter

If you insert a backslash (\) before the first directory name in path,
MS-DOS treats the directory as a subdirectory of the root
directory--regardless of your current directory. If you do not insert a
backslash before the first directory name in path, MS-DOS treats the
directory as a subdirectory of the current directory.

Deleting the current directory

You cannot use RMDIR to delete the current directory. You must first change
to a different directory (not a subdirectory of the current directory) and
then use RMDIR with a path. If you attempt to delete the current directory,
MS-DOS displays a message in the following format:

    Attempt to remove current directory - drive:path

MS-DOS also displays this message if you attempt to delete a directory that
has been redirected by using the SUBST command.