Receiving java.lang.NoClassDefFoundError using SoapUI NG PRO

Hi,

I'm trying to run few scripts on SOAPUI NG PRO and getting 'java.lang.NoClassDefFoundError' at line 99. Code at line 99 as follows:

        Cell cell = row.createCell(j);
                                  if (j==0)
                                  {
                                                cell.setCellValue(testcaseName); - this is line 99
                                  }

Line 99 is writing 'testcaseName' to the output excel file.

If I run the same script using SOAPUI Pro 5.1.0 then its running fine without any errors.

Can someone please let me know how to correct this error?