Phil,
The folder ASP.NETv1.1 contains the CuteEditor filles for the ASP.NET framework 1.1. The folder ASP.NETv1.0 contains the CuteEditor filles for the ASP.NET framework 1.0.
Because Validate Request attribute is *only* present in ASP.NET v1.1. It looks like your server is running on ASP.NET 1.0, so you get that error.
Please use the files in the folder ASP.NETv1.0 instead.
asp.net Chat http://cutesoft.net/ASP.NET+Chat/default.aspx
Web Messenger: http://cutesoft.net/Web-Messenger/default.aspx
asp.net wysiwyg editor: http://cutesoft.net/ASP.NET+WYSIWYG+Editor/default.aspx
asp wysiwyg html editor: http://cutesoft.net/ASP
asp.net Image Gallery: http://cutesoft.net/ASP.NET+Image+Gallery/default.aspx
Live Support: http://cutesoft.net/live-support/default.aspx