I am receiving a NullPointerException when I call Workbook.write().  The trace 
is below.  I've also attached the method in which I call write().


java.lang.NullPointerException 

.at org.apache.poi.hssf.record.SSTSerializer.calculateUnicodeSize
(SSTSerializer.

.at org.apache.poi.hssf.record.SSTRecordSizeCalculator.getRecordSize
(SSTRecordSi

.at org.apache.poi.hssf.record.SSTRecord.getRecordSize(SSTRecord.java:499) 

.at org.apache.poi.hssf.model.Workbook.getSize(Workbook.java:756) 

.at org.apache.poi.hssf.usermodel.HSSFWorkbook.getBytes(HSSFWorkbook.java:768) 

.at org.apache.poi.hssf.usermodel.HSSFWorkbook.write(HSSFWorkbook.java:732) 

.at com.timeinc.tcs.compsub.admin.DisplayXLS.process(DisplayXLS.java:132) 

.at com.timeinc.tcs.compsub.admin.DisplayXLS.doGet(DisplayXLS.java:59) 
=============================================================================

public String process() throws IOException{

    //System.out.println("***"+props.SHEETNAME_RPT);
	File temp = File.createTempFile("CSB",".xls");
	temp.deleteOnExit();
	   	
	try{			
		
		// SET UP WORKBOOK AND SHEETS
		wb = getTemplate();
		setStyles();
		setReportSheet(); 
			
		setReportHeaderSheet();
		
		setInstructionSheet(); 
		BufferedOutputStream bos = new BufferedOutputStream(new 
FileOutputStream(temp));
		wb.write(bos);	
		bos.flush();
	  	bos.close();
		
	} catch (Exception e) {
		e.printStackTrace(System.out);	
	}
	
	return temp.getCanonicalPath();
}