created an attachment (id=172187)
test report

description:
  error is thrown out when preview gantt type chart

test build:
birt2.6.1 v20100618-1142

step to reproduce:

1. use the report attached
2. preview

expect result:
report can preview correctly

actual result:
error is thrown out

error log:
caused by: org.eclipse.birt.chart.exception.chartexception: the data entry has a value of invalid type.
	at org.eclipse.birt.chart.extension.datafeed.ganttdatasetprocessorimpl.validateganttentrydata(ganttdatasetprocessorimpl.java:126)
	at org.eclipse.birt.chart.extension.datafeed.ganttdatasetprocessorimpl.populate(ganttdatasetprocessorimpl.java:71)
	at org.eclipse.birt.chart.internal.datafeed.dataprocessor.fillseriesdataset(dataprocessor.java:1367)
	at org.eclipse.birt.chart.internal.datafeed.dataprocessor.generateruntimeseries(dataprocessor.java:814)
	at org.eclipse.birt.chart.internal.datafeed.dataprocessor.generateruntimeseries(dataprocessor.java:1467)
	at org.eclipse.birt.chart.internal.datafeed.dataprocessor.generateruntimeseries(dataprocessor.java:508)
	at org.eclipse.birt.chart.factory.generator.binddata(generator.java:652)
	at org.eclipse.birt.chart.reportitem.chartreportitempresentationbase.binddata(chartreportitempresentationbase.java:683)
	at org.eclipse.birt.chart.reportitem.chartreportitempresentationbase.onrowsets(chartreportitempresentationbase.java:801)
	at org.eclipse.birt.chart.reportitem.chartreportitempresentationproxy.onrowsets(chartreportitempresentationproxy.java:108)
	at org.eclipse.birt.report.engine.presentation.localizedcontentvisitor.processextendedcontent(localizedcontentvisitor.java:1014)
	... 59 more
fixed. null value is allowed the gantt entry and this entry will not be drawn in rendering.
verified in daily build v20100621-0630