Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException:

i am getting this problem while running my program. Please help. The error report points at line no 17.

import java.io.*;

public class Rename{

public static void main(String args[]){
File dir=new File("C:\\irla_pdf\\eme\\MPS_Pdfs_10_2011"); //enter the location where mps pdf files are kept
String [] fname=dir.list();
if(fname==null)
System.out.println("no files");
else{



for(int i=0;i<dir.length();i++){


File pdffilename=new File("C:\\irla_pdf\\eme\\MPS_Pdfs_10_2011\\"+fname[i]); //enter the location where mps pdf files are kept

//System.out.println("existing name "+pdffilename);
String newname=fname[i].substring(11,19)+".pdf";
File newfilename=new File("c:\\irla_pdf\\eme\\pdf1011\\"+newname);//enter the location where renamed pdf files are to be kept
//System.out.println("new filename "+newfilename);
if(pdffilename.renameTo(new File("c:\\irla_pdf\\eme\\pdf1011\\"+newname))){
//System.out.println("renamed");
}
else
System.out.println("error");
//System.out.println(fname[i]);
//System.out.println(newname);



}
}
}
}