EPC error while using at endat in Loop

Hi all

I have used following coding in my prog.

loop at wa_plant.

LOOP at LV_PURREQ into gs_PURREQ WHERE WERKS-WERKS EQ WA_PLANT-WERKS.

-

-

at last

print text....

endat.

endloop

endloop.

but i checked in EPC

its showing following error

The LOOP statement processing will be limited

(FROM, TO and WHERE additions in LOOP)

Interaction with group change processing (AT NEW, ...) is undefined

(The message can be hidden with "#EC *)

How can i solve?