I am also having this problem. The scripting error reported by IE I am getting when I click on edit to try and change the timestamp is:
Line 132 Char 2 Error Object does not support this property or method
I am using a theme (ADropInTheSea) which I can’t even locate at WordPress anymore, and it’s not listed as a compatibale theme with 2.7
http://codex.ww.wp.xz.cn/Themes/Theme_Compatibility/2.7
So I switched to a compatible theme and got the same error. I do not think this is a theme or plugin issue.
In firefox I use the error console and it says I am getting a syntax error, specifically:
Error: uncaught exception: [Exception… “Component returned failure code: 0x80070057 (NS_ERROR_ILLEGAL_VALUE) [nsIWebNavigation.loadURI]” nsresult: “0x80070057 (NS_ERROR_ILLEGAL_VALUE)” location: “JS frame :: chrome://global/content/viewSource.js :: viewSource :: line 156” data: no]
Maybe someone who understands these error codes can say. My guess is someone needs to edit wp-admin/js/post.js or another file in that directory, but I don’t know how.