INFOrow 3 or column UserName does not exist in xls

Hi I am created the JAR file and placed in the Lib folder and when i run the below groovy script i get the message "Info row or column does not exist in xls.

import com.soapuitutorial.property.*
Xls_Reader xls = new Xls_Reader("C:\\Users\\JANGAMS\\TestCases.xls")
log.info xls.getCellData("Logintest", "UserName", 3)


Please can someone help me on this.