Bug 163018 An error extension will lead the report contain chart can't be opened and can not new a report.
Details: An error extension will lead the report contain chart can't open In org.eclipse.birt.report.tests.model has an error extension. When run the birt use workbenck, the report contain chart can't be opened and it can not new a report.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/metadata/PeerExtensionLoader.java
new String[]{className},
						ExtensionException.DESIGN_EXCEPTION_FAILED_TO_CREATE_INSTANCE );
			}
			elementDefn.extensionPoint = EXTENSION_POINT;
			MetaDataDictionary.getInstance( ).addExtension( elementDefn );
		}
		/**
		 * Loads one property definition of the given element.
		 * 
		 * @param elementTag
		 *            the element tag
		 * @param propTag
		 *            the property tag
		 * @param elementDefn
		 *            element definition
		 * @return the property definition
		 * @throws ExtensionException
		 *             if the class some attribute specifies can not be
		 *             instanced.
		 */
		ExtensionPropertyDefn loadProperty( IConfigurationElement elementTag,
				IConfigurationElement propTag, ExtensionElementDefn elementDefn )
				throws ExtensionException
		{
			
			String name = propTag.getAttribute( NAME_ATTRIB );
			String type = propTag.getAttribute( TYPE_ATTRIB );
			checkRequiredAttribute( NAME_ATTRIB, name );
			checkRequiredAttribute( TYPE_ATTRIB, type );