Sherri,
Just to get some language straight -- "A" is for August is a thread (not forum, Round Robin is the forum where that thread is located).

At the bottom of the page on that thread, at the same location where the box would be to post -- it would say "log in". Click that and log in.

Then on that forum page -- Up in your Browser (the window/program of your computer where you are viewing the internet), click Refresh. (Whatever button is there for refreshing the page.) You are seeing an "old version" of the webpage from the memory of your computer instead of the new, I'm-already-logged-in version.

Login. Refresh, if the box is not showing.