Correct. the Framework 1.x .dll is the one I've been using.
Can you try the latest CuteEditor.Net version in VS2003?
To replicate what I did, Just drag-n-drop the CuteEditor.Net control after you have added the
Framework 1.x\bin\CuteEditor.dll and added the control to the Toolbox. Hit Run. The error should appear before the page shows.