[jdom-interest] java.util.ConcurrentModificationException

[X.P.Pratibha :-)]

Hi all,
         I am having a ListIterator to traverse my JDOM. When I find a 
list of my interest I am removing it using remove()...Its throwing 
ConcurrentModificationException..Any thoughts will be of great help.
Please tell me whats going wrong???

while(listxpp.hasNext())
                {
		     int removecount=0;
		      Element FWnode = ((Element) 
listxpp.next()).getChild("FirewallRule");
		      String ID =FWnode.getAttributeValue("id");	

                      while(listxpp2.hasNext())
			{
			Element FWnode2 = ((Element) listxpp2.next()).getChild("FirewallRule");
			String ID2 = FWnode2.getAttributeValue("id");
			
			 if(ID.equals(ID2))
			 {
			removecount++;
			if(removecount>1)
			{
				

                                listxpp2.remove();
                                		}
						 }
		              }
		
		              while(listxpp2.hasPrevious()){
		              Element PWnode = ((Element) 
listxpp2.previous()).getChild("FirewallRule");
				  }
            }