I’m using the Conference-files, shipped with the EPiServer Sample Code, to make a page that can be used for discussions (a forum). Mostly I’ve made changes to the layout, so the functionality is pretty much the same as in the original Conference-files. Already from the start I’ve gotten an “Error on page”, and nothing on the page that has anything with the Conference-functionality to do respond on the page – in IE! The page works as it should in Firefox! When I first enter the page I get an “Object expected” (line:475, char: 1, code: 0, URL: to my page). Then, (after ignoring this, of course  ) when trying to expand the explorer tree, another error occurs too: “’containerElement’ is undefined” (line: 37, char: 3, code:0, URL: to my page), and nothing expands at all. In Conference.aspx.cs I had the following lines in Page_load: RegisterScriptFile("util/javascript/system.js"); And then I found something here at this forum, something that sounded kind of like my problems. And someone said that this line should be inserted into the aspx-file: if (!Page.IsClientScriptBlockRegistered("system.js")) { RegisterClientScriptBlock("system.js", ""); } So I replaced the RegisterScriptFile-line with the if-lines, and my problems were cut in half. I could expand the tree, but I couldn’t read the posted discussions, when trying nothing would happen. I continued with the development in Firefox, thinking that I would deal with these IE-problems later. And a few days later I was thinking about this problem again, with no ideas what to do. I took back the RegisterScriptFile-line again, compiled and looked for any changes, but I didn’t get any wanted effects, so I returned to the if-lines and all of a sudden I discovered that it worked also in IE – just like that! All of a sudden and out of the blue, the page worked fine in IE too. But I haven’t got a clue why, and what did it. Happy, I finished the development and sent everything to production… Only to discover that all of a sudden, these former problems and errors are back again!!! This time in production, and since it just worked out of the blue while developing it, I simply don’t know what to do to make it go away! Both errors are back, I can read the posted discussions, but I cannot expand the explorer tree. Please, can anyone help me?!