I'm not sure exactly what you mean by "in a frame," and since I don't have access to your screen reader, it would be difficult for us to troubleshoot the issue further. The forums do make use of AJAX for the quick reply box, which may be the problem. However, it is integral to how the forums work and cannot be turned off.

I'm not sure if this is a problem regardless of whether you're using the "Quick Reply" box at the bottom of the thread, or also when you click on a "Reply" button to a specific post. It may be that if you only use the Reply button, the issue may not be present?

Sorry I couldn't be of more assistance with this issue.

DocJohn