need help to call screen
i am working on userexit for tcode MB1A.
if error message is than message should come and screen should not go for next screen.
IF int_mara-mtart = 'ZAMT' and i_mseg-BWART = '201'.
MESSAGE e001(zmsg1) .
<b>how i can call screen which has given error message</b>
now what happing is that error message is coming but going for next screen.
but i want current screen only.