David, what specifically are you trying to reply to?
If you are trying to reply to dog classifieds, those are non-repliable. Years ago, they were repliable. But we found, particularly on the lab puppy threads, that folks would feign replies to bump an ad to the top of the heap. Or sometimes folks were heckling someone for breeding an EIC carrier or some other such thing. We even had some users that were posting from more than one account on the same computer carrying on conversations with themselves, in an effort to keep their ads on top.
Many folks had trouble (myself included) staying logged in after the server move and software upgrade. This may be related to your issue as well. If that is the case, you may want to clear cookies and history, delete your old RTF bookmark, log in manually to http://www.retrievertraining.net/forums/ and check the "remember me" box. Then after you are logged in, create a new bookmark.
This should not be too hard to get fixed. Please PM me and we'll get it worked out.