When I view source where the chart is displayed I see:
"../DynamicWebCharts/open-flash-chart.swf?data=../DynamicWebCharts/Data/invoice_selected_dataparser1.asp?"
If you were passing the data properly it would look something like:
"../DynamicWebCharts/open-flash-chart.swf?data=../DynamicWebCharts/Data/invoice_selected_dataparser1.asp?PERIOD=200904"
also it appears there may be a bad path on the include file. Look at the error when viewign the page directly:
invoice_selected_dataparser1.asp
Maybe find and replace the instances of that page reference, and see if it works.