Phew, I updated ckEditor and that seems to have fixed the pasting from Word.
But... I still see an error on every page:
Webpage error details
User Agent: Mozilla/4.0 (compatible; MSIE 8.0; Windows NT 5.1; Trident/4.0; .NET CLR 2.0.50727; .NET CLR 3.0.4506.2152; .NET CLR 3.5.30729; .NET4.0C; .NET4.0E)
Timestamp: Thu, 21 Jun 2012 20:27:48 UTC
Message: 'cssmw' is undefined