Need Help with DCL

Hello Cad tutor

I Need Help with DCL File

DCL CODE

Insert_Block :dialog {label="Insert Block:";
            :boxed_radio_column{label="Input Coordinates";
            :edit_box{label="Easting:";
                       key="est";
                       edit_width = 20;
                       edit_limit = 20;
                       mnemonic = "E";
                       //alignment = "Right";
                       value= "0";
                       is_tab_stop = true;
                     }
            :edit_box{label="Northing:";
                      
                       key="north";
                       edit_width = 20;
                       edit_limit = 20;
                       mnemonic = "N";
                       //alignment = "Right";
                       value= "0";
                       is_tab_stop = true;
                     }
                  }
            :boxed_radio_row{label="Block";
            :button{label="Select Block:";
                     key="Block";
                     	fixed_width = true;
                //alignment = centered;
                     is_default = true;
                   }
                   }

                   :text {   
                             key="file";
  
                            
                            
           
                            }
                 
                 
            :boxed_radio_row{
                      :button{label="PLOT";
                              key="accept";
                              fixed_width = true;
                              is_default=true;
                             }
                      :button{label="EXIT";
                              key="cancel";
                              fixed_width = true;
                              is_default=false;
                              is_cancel=true;
                             }
                  }

                  :text_part {label="Designed and Created:";
                              
                             }
                  :text_part {label="By Ganesh Shetty";
                             }
            }

                  
              
                      

Autolisp Code:

(defun c:TEst (/ est north filename flag dcl_id)
 (setq flag 4)
 (setq filename "No Block Selected")
 (setq dcl_id (load_dialog "C:/Insert_point.dcl"))
 (while (> flag 2)
   (if	(not (new_dialog "Insert_Block" dcl_id))
     (exit)
   )
   (set_tile "file" filename)
   (action_tile "cancel" "(done_dialog 0)")
   (action_tile "accept" "(done_dialog 1)")
   (action_tile "Block" "(done_dialog 4)")
   (action_tile "est" "(setq est $value)")
   (action_tile "north" "(setq north $value)")
   (setq flag (start_dialog))
   (if	(= flag 0)
     (princ "\nFunction Cancelled:")
   )
   (if	(= flag 1)
     (progn
(setq cor (strcat est "," north))
(command "-insert" filename "_non" cor "" "" "")
(command "Zoom" "e")
     )
   )


   (if	(= flag 4)
     (progn
(setq filename (getfiled "Select Block" "" "dwg" )
(if (= filename nil)
  (setq filename "Block not Selected")
)
      )
    )

   )
 (unload_dialog dcl_id)
 (princ)
)

Here i had Two problem

1. after selecting block Easting (X) & Northing (Y) Values i must reenter both Values

2.if the Block is not Found i want to put error massage

please help me to fix this