android apache poi error

here is my code for generating backup for my database i using apache poi for that purpose but it show some errors when i execute.

i start with HSSF worksheet and create a sheet and add details from my database and save that file in the specific loaction on sd card.

 HSSFWorkbook backup=new HSSFWorkbook();
    HSSFSheet sheet=backup.createSheet("Contact_Backup");
Map<String, Object[]> data = new HashMap<String, Object[]>();
            sq = md.getReadableDatabase();

            Cursor mCursor = sq.rawQuery("SELECT * FROM "
                    + MyDatabase.TABLE_NAME, null);

            if (mCursor.moveToFirst()) {
                do {
                    idbackup.add(mCursor.getString(mCursor.getColumnIndex(MyDatabase.KEY_ID)));
                    namebackup.add(mCursor.getString(mCursor.getColumnIndex(MyDatabase.KEY_NAME)));
                    numberbackup.add(mCursor.getString(mCursor.getColumnIndex(MyDatabase.KEY_NUM)));
                    addressbackup.add(mCursor.getString(mCursor.getColumnIndex(MyDatabase.KEY_ADDR)));
                    mailbackup.add(mCursor.getString(mCursor.getColumnIndex(MyDatabase.KEY_MAIL)));
                } while (mCursor.moveToNext());
            }
            if (idbackup.size() != 0) {
                int j = 2;
                for (int i = 0; i < idbackup.size(); i++) {
                    data.put(String.valueOf(j), new Object[]{idbackup.get(i), namebackup.get(i), numberbackup.get(i), addressbackup.get(i), mailbackup.get(i)});
                    j++;

                }
            }


            Set<String> keyset = data.keySet();
            int rownum = 0;
            for (String key : keyset) {
                Row row = sheet.createRow(rownum++);
                Object[] objArr = data.get(key);
                int cellnum = 0;
                for (Object obj : objArr) {
                    Cell cell = row.createCell(cellnum++);
                    if (obj instanceof Date)
                        cell.setCellValue((Date) obj);
                    else if (obj instanceof Boolean)
                        cell.setCellValue((Boolean) obj);
                    else if (obj instanceof String)
                        cell.setCellValue((String) obj);
                    else if (obj instanceof Double)
                        cell.setCellValue((Double) obj);
                }
            }
   try {
            File directory = new File("/sdcard/BulkMessenger/backups"); /*creating the file directory
            directory.mkdir();
            long date = System.currentTimeMillis();

            SimpleDateFormat sdf = new SimpleDateFormat("MMM MM dd, yyyy h:mm a");
            String dateString = sdf.format(date);
            File file = new File(directory, dateString+"backupcontact.xls");
            FileOutputStream out = new FileOutputStream(file);
            backup.write(out);
            out.close();
            Toast.makeText(getApplicationContext(),"Successfully backup generated in backup",Toast.LENGTH_LONG).show();


        } catch (FileNotFoundException e) {


            e.printStackTrace();
        } catch (IOException e) {

            e.printStackTrace();
        }
    }

my error log is given below in it filenotfound exception that what i got.

07-08 09:52:38.250 15615-15615/com.example.web03.bulkmessenger E/dalvikvm: Could not find class 'java.awt.font.FontRenderContext', referenced from method org.apache.poi.hssf.usermodel.HSSFSheet.autoSizeColumn

thanks for help in advance!

its related to my file directory thats exception is raised!! thanks for advice guys