Stuart,
Can you try the following code?
<%@ Page Language="C#"%>
<%@ Register TagPrefix="CE" Namespace="CuteEditor" Assembly="CuteEditor" %>
<html>
<body>
<form runat="server" ID="Form1">
<CE:Editor id="Editor1" runat="server" Height="100%" ></CE:Editor>
</form>
</body>
</html>
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asp wysiwyg html editor: http://cutesoft.net/ASP
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