Bug 140542 label can't be displayed without resource file or unmatched key
Steps to reproduce: 1.New a report, add a lable with text "aaa" 2.Add a resource file for the report, set key to "key1", value to "actuate", apply the value to the label 3.Clear the resource file in Property Editor->General->Resource File (or change the key to "abc") 4.Preview the report Expected result: 1.Display label text "aaa" on preview or 2.Give a warning message to say resource file is not found or unmatched key Actual result: Nothing displays on preview
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/core/Module.java
*            <li><code>IResourceLocator.IMAGE</code>
	 *            <li><code>IResourceLocator.LIBRARY</code>
	 *            </ul>
	 *            Any invalid value will be treated as
	 *            <code>IResourceLocator.IMAGE</code>.
	 * @return the <code>URL</code> object if the file with
	 *         <code>fileName</code> is found, or null otherwise.
	 */
	public URL findResource( String fileName, int fileType )
	{
		URL url = getSession( ).getResourceLocator( ).findResource(
				(ModuleHandle) getHandle( this ), fileName, fileType );
		return url;
	}
	/**
	 * Loads library with the given library file name. This file name can be
	 * absolute or relative. If the library doesn't exist or fatal error occurs
	 * when opening library, one invalid library will be added into the library
	 * list of this module.
	 * 
	 * @param libraryFileName
	 *            library file name
	 * @param namespace
	 *            library namespace
	 * @return the loaded library
	 * @throws DesignFileException
	 *             if the library file has fatal error.
	 */
	public Library loadLibrary( String libraryFileName, String namespace )
			throws DesignFileException