I think I know what causing the error. For some reason, that "1" was included in the JSON output and caused the error. In CF Admin, there is a setting to debug AJAX. Turn it on and trace it by looking at the output from AJAX.
Enable AJAX Debug Log Window
Allows display of the AJAX debug log window when the cfdebug flag is passed in the URL. If you disable this option, the AJAX debug log window does not display, even if the cfdebug flag is specified.