Here are some useful tips if you get weird stuff happening with your Wordpress installation. I’ve experienced all of these, and the fixes seem to work.
Cannot write text or edit text in IE7
If you’re using IE7 and you try and edit an existing post, or create a new one, with the ‘Visual’ editor in operation, you are either unable to enter text or existing text disappears. On the Status bar you may see a Javascript error warning, which will include such phrases as Permission Denied or ”this.contentWindow.document’ is null or not an object’.

