I have a small page with a dynamic ajax outputPanel that gets rerendered on certain user action and it all works good until the newly loaded pageBlock contains rich edit field (rendered with apex : inputField). Then, I get this javascript error and the entire viewport gets blanked. The initial page load does not contain rich edit field (in case it makes a difference, like it did with calendar popups)

Error:

Object doesn't support this property or method

3_3_0.GAorg.ajax4jsf.javascript.AjaxScript, line 173 character 590

By the looks of call stack it appears as if the Ajax caller failed to parse the response from SF and tried to raise an error and then ran into a missing property/method. The error location is pointing to a piece of code containing "finally{window.document.open=oldDocOpen;}" if that makes any difference as well.