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/EncryptionHelperExtensionLoader.java
{
	/**
	 * The name of extension point
	 */
	public static final String EXTENSION_POINT = "org.eclipse.birt.report.model.encryptionHelper"; 
	private static final String ENCRYPTION_HELPER_TAG = "encryptionHelper"; 
	/**
	 * Default constructor
	 */
	public EncryptionHelperExtensionLoader( )
	{
		super( EXTENSION_POINT );
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.birt.report.model.metadata.ExtensionLoader#loadExtension(org.eclipse.birt.core.framework.IExtension)
	 */
	void loadExtension( IExtension extension ) throws ExtensionException,
			MetaDataException