Enabling the screen after error message

Hello,

By using the EXIT: EXIT_SAPLMLSP_030 i am displaying the error message based on some conditions in ML81N (Service entry sheet).

while saving the service entry sheet i am able to display the error message successfully.

After displaying the error message the screen becomes disabled and it is not allowing to change the values.

But the user wants to change the values after displlaying the error message.

I tried the following ways.

     >Set screen '0400'.

     > message type 'S/I' display like 'E'.

     > leave screen

     > Leave to LIST-PROCESSING

               " It is displaying error message saying that in subscreen we can not set the screeen ".

     > i tried displaying the error message as popup

Used the following function modules.

     > HR_BEN_SHOW_ERROR_POPUP

     > C14ALD_BAPIRET2_SHOW

     > POPUP_WITH_TABLE_DISPLAY_OK

     > POP_UP_TO_CONFIRM

Please suggest me any other way ro acieve the requirement.

Thanks in Advance.

Regards,

Dorababu P