gistfile1.txt

<s:RadioButton 
                width="100%"
                label="{resourceManager.getString('application', 'PREF_FITWIDTH')}"
                styleName="white"
                selected="{controller.user.preferences.defaultDocumentZoom == resourceManager.getString('application', 'PREF_FITWIDTH')}"
                group="{defaultDocumentZoom}"/>

to:
private static const PREF_WIDTH = resourceManager.getString('application','PREF_WIDTH');

<s:RadioButton 
                width="100%"
                label="{PREF_WIDTH}"
                styleName="white"
                selected="{controller.user.preferences.defaultDocumentZoom == PREF_WIDTH}"
                group="{defaultDocumentZoom}"/>