User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:5.0) Gecko/20100101 Firefox/5.0 Build ID: 20110615151330 Steps to reproduce: To produce this error I can open a new tab or click a link to make a page load in the current tab. It doesn't work every time, which is why the bug is frustrating. Actual results: A pop-up error that stated "Error: document.DocumentElement is null." appeared. Expected results: The error shouldn't have occurred.
Does the issue still occur if you start Firefox in Safe Mode? http://support.mozilla.com/en-US/kb/Safe+Mode How about with a new, empty profile? http://support.mozilla.com/en-US/kb/Basic%20Troubleshooting#w_8-make-a-new-profile
Mozilla/5.0 (Windows NT 6.1; rv:9.0a1) Gecko/20110817 Firefox/9.0a1 Reporter, are you still experiencing this issue? Did you had the chance to try what was suggested in Comment 1?
(In reply to Tim (fmdeveloper) from comment #1) > Does the issue still occur if you start Firefox in Safe Mode? > http://support.mozilla.com/en-US/kb/Safe+Mode > > How about with a new, empty profile? > http://support.mozilla.com/en-US/kb/Basic%20Troubleshooting#w_8-make-a-new- > profile (In reply to Simona B from comment #2) > Mozilla/5.0 (Windows NT 6.1; rv:9.0a1) Gecko/20110817 Firefox/9.0a1 > > Reporter, are you still experiencing this issue? Did you had the chance to > try what was suggested in Comment 1? I've not had a chance to try this until now, so I'm going to run it for awhile on safe mode. I'm pretty sure it's conflicting add-ons or something of the add-on nature. On a side note, I can get the same error by hitting the back button. When I was on the page initially, I didn't get the error, only after I hit the back button, which is interesting.
Closing bug as Incomplete - if you are still experiencing this issue or have more information to provide feel free to post back here and we can re-open the bug. You can also get assistance by visiting the Firefox help site -> https://support.mozilla.com/en-US/kb/ask