I would like to take a look at your project
1: This sounds like a bug. RW should not lock up. But it’s impossible to even guess at what might be causing it without knowing all of the details. I’d recommend zipping up your file, and your entire addons folder, sharing the zip file on dropbox (or whatever your favorite sharing service is), and sending the link over to our support folks: http://yourhead.com/support – tell them exactly what they should do to make the lockup happen.
2: This sounds like trouble with content or code. This answer is about scrolling – but I would suspect the same root cause: http://cafe.yourhead.com/?qa=153/why-does-stacks-scroll-to-the-top-of-the-page-when-make-changes&show=153#q153
Specifically, that there is some content on one of these pages that is confusing the web-rendering – that is causing two copies of the stack to appear.