This is a known bug when using Outlook Express 6 after you've installed Office 2007 - for some reason OE6 isn't compatible with the Office 2007 dictionaries.
Microsoft's solution is to download and use Windows Live Mail instead.....
Well, I'm writing this on my new Dell Vostro 3300 which has both OE6 and Windows Live Mail. I really hate Windows Live Mail right now because it won't let me order my folders the way
I require - it orders them in the way some technogeek
thinks I want them......
Microsoft knows all about this OE6 / Office 2007 spell check bug (it only works in French..), but seems totally uninterested in fixing it.
And please don't anyone witter on about how good other browsers and e-mail systems may or may not be - or what wonderful things Immac make - this is a specific Outlook Express query!
The link you provided, BOAC, is too complicated for the majority of home users who just want their spell checker back. Why isn't Microsoft fixing its own bugs?