I was continuing to have problems responding to comments; in fact the problem got a little worse. I tracked down through a Google Forum that they were aware of the problem. In the meantime they recommended that I switch to a pop-up box format for comments. I have switched over to this format and was able to respond to a comment. So hopefully this will be a working solution. For those who have commented before be aware that the format is now slightly different than before.
Thanks for your patience,