A list gets locked when a list owner issues a GET command with the intent
to  update  it. This  is  because  the list  owner  is  going to  send  a
replacement copy. If LISTSERV processed  your request, it would be undone
when  the  replacement  list  is received.  Sometimes  people  forget  to
actually update the list, and it  remains locked. Some owners (mostly for
closed,  internal lists)  don't want  the list  to change,  and leave  it
permanently locked. A locked list  can still receive and distribute mail,
it just can't be updated.
 
  Eric