Adam,
I downloaed the latest version and replaced all files and the error still exists.
When you upload an image, you don't see the error message in the browser. What happens is that each time the Application_Error (ByVal sender As Object, ByVal e As EventArgs) in the Global.asax will be fired. The error message is logged as
Error Caught in Application_Error event
Error in:
http://localhost/Test/CuteEditor_Uploader_Resource.axd?type=file&file=Continuous.gif
Error Message: Path '/CuteEditor_Uploader_Resource.axd' was not found.
Stack Trace: at System.Web.HttpNotFoundHandler.ProcessRequest(HttpContext context)
at System.Web.HttpApplication.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute()
at System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously)
Hope this information helps you to find the error.
Joerg