I ran into this problem and after a lot of searching I found that in the ext-all.js (included in Ext 3.4, included with Valence 2.2) there is this line of code:
We put this in valence.js to override in all our apps:
Code:
Ext.chart.Chart.CHART_URL = 'http:/' + '/yui.yahooapis.com/2.8.2/build/charts/assets/charts.swf';
Code:
Ext.chart.Chart.CHART_URL = '/extjs/resources/charts.swf';