KathrynBassett wrote:

I can read the messages,
and I assume that when posting a new thread, that it's still ok to
cite an old thread like I did?

Sure it's OK to cite a prior thread like that. However, you were asking why
you couldn't reply but you never stated what client you were using and how
you were accessing the group. The ability to reply or not depends on the
client and the method it uses to access the group, not on any of the threads
in the group.
--
Brian Tillman