Error message in user Exit

Hi friends,

Iam working on sone userexit in tcode Ko01 . actually i have to through the error message ...break point comes to that point it is not throughting that message...the message format i have used is

MESSAGE msgtypemsgnumber(messageid) WITH 'text message'.

the FM in which the include is there does not contain exceptions then can u plz tell me how i should through the error message....

thanks in advace...