Can not instantiate class org.eclipse.birt.chart.reportitem.ChartReportItem Generatio

[Jack]

Hi,
I'm trying to generate a html document from a design.
This design contains a table and a barchart
When I execute RunAndRenderTask obtains this exception:

ATTENTION: Can not instantiate class org.eclipse.birt.chart.reportitem.ChartReportItem
 GenerationImpl with property class.
org.eclipse.birt.core.framework.FrameworkException :
 org.eclipse.core.runtime.CoreException: Plug-in org.eclipse.birt.chart.reportitem was 
unable to load class org.eclipse.birt.chart.reportitem.ChartReportItemGenerationImpl.
at org.eclipse.birt.core.framework.eclipse.EclipseConfigurationElement.createExecutableExtension
(EclipseConfigurationElement.java:38)
Caused by: org.eclipse.core.runtime.CoreException:
 Plug-in org.eclipse.birt.chart.reportitem was unable
 to load class org.eclipse.birt.chart.reportitem.ChartReportItemGenerationImpl.
at org.eclipse.core.internal.registry.osgi.RegistryStrategyOSGI.throwException
(RegistryStrategyOSGI.java:165)
at org.eclipse.core.internal.registry.osgi.RegistryStrategyOSGI.createExecutableExtension
(RegistryStrat egyOSGI.java:151)
at org.eclipse.core.internal.registry.ExtensionRegistry.createExecutableExtension
(ExtensionRegistry.jav a:759)
at org.eclipse.core.internal.registry.ConfigurationElement.createExecutableExtension
(ConfigurationElement.java:243)
at org.eclipse.core.internal.registry.ConfigurationElementHandle.createExecutableExtension
(ConfigurationElementHandle.java:51)
at org.eclipse.birt.core.framework.eclipse.EclipseConfigurationElement.createExecutableExtension
(EclipseConfigurationElement.java:34)
... 12 more
16 mai 2007 18:07:09 org.eclipse.birt.report.engine.extension.internal.ExtensionManager createObject
Caused by: org.eclipse.core.runtime.CoreException:
 Plug-in org.eclipse.birt.chart.reportitem was unable to load class
org.eclipse.birt.chart.reportitem.ChartReportItemPresentationImpl.
at org.eclipse.core.internal.registry.osgi.RegistryStrategyOSGI.throwException
(RegistryStrategyOSGI.jav a:165)
at org.eclipse.core.internal.registry.osgi.RegistryStrategyOSGI.createExecutableExtension
(RegistryStrat egyOSGI.java:151)
at org.eclipse.core.internal.registry.ExtensionRegistry.createExecutableExtension
(ExtensionRegistry.jav a:759)
at org.eclipse.core.internal.registry.ConfigurationElement.createExecutableExtension
(ConfigurationEleme nt.java:243)
at org.eclipse.core.internal.registry.ConfigurationElementHandle.createExecutableExtension
(ConfigurationElementHandle.java:51)
at org.eclipse.birt.core.framework.eclipse.EclipseCon figurationElement.createExecutableExtension
(EclipseConfigurationElement.java:34)
... 17 more
16 mai 2007 18:07:10 org.eclipse.birt.report.data.oda.sampledb.Sampledb 
Plugin removeDatabase
ATTENTION: Failed to remove one or more file in temp db directory:
 C:\DOCUME~1\egomez\LOCALS~1\Temp\/BIRTSampleDB_1179331625047_19c5048

why?
how can I resolve this?