Hi jojolevy,
Can you post your example page url? So we can check it for you directly.
Please try the example page below. Does it get the same issue?
<%@ Page Language="C#" AutoEventWireup="True" %>
<%@ Register Namespace="CuteEditor" Assembly="CuteEditor" TagPrefix="CE" %>
<html>
<body>
<form id="Form1" runat="server">
<CE:Editor ID="editor1" runat="server">
</CE:Editor>
</form>
</body>
</html>
Get it on all browsers?
Please clean your browser cache and download this package http://www.cutesoft.net/downloads/folders/21904/download.aspx. Then re-deploy the "CuteSoft_Client" folder to try again.
Regards,
Ken