Bug 132914 "Invalid page number" error message is hard coded.
"Invalid page number" error message is hard coded in DocumentProcessor.java. This must be externalized into *.properties file. If there are other hard coded error messages, please also externalize.
viewer/org.eclipse.birt.report.viewer/birt/WEB-INF/classes/org/eclipse/birt/report/presentation/aggregation/parameter/ScalarParameterFragment.java
.getAttribute( "attributeBean" ); 
		assert attrBean != null;
		
		Object paramValueObj = null;
		String parameterValue = null;
		if ( attrBean.getParametersAsString( ) != null )
			paramValueObj = attrBean.getParametersAsString( ).get(
					parameterBean.getName( ) );
		if ( paramValueObj != null )
			parameterValue = paramValueObj.toString( );
		
		switch ( parameter.getDataType( ) )
		{
			case ParameterDefinition.TYPE_STRING :
			{
				
				
				parameterBean.setRequired( false );
				if ( paramValueObj == null && !parameter.allowNull( ) )
				{
					parameterBean.setRequired( true );
				}
				else if ( paramValueObj != null
						&& ( (String) paramValueObj ).length( ) <= 0
						&& !parameter.allowBlank( ) )
				{
					parameterBean.setRequired( true );
				}
				break;
			}