"msg_alert" must be declared?

Oracle FORMS 10.1.2.3.0

Hello to all.

This should be a pretty easy one, but I'm having trouble with "msg_alert".

It keeps telling me that needs to be declared.

...

TEXT_IO.FCLOSE(IN_FILE);

msg_alert('Excel file has been created!','I',FALSE);

EXCEPTION

WHEN Others THEN

TEXT_IO.FCLOSE(IN_FILE);

MSG_ALERT('Error while writing file.'||sqlerrm,'I',FALSE);

END;

identifier 'MSG_ALERT' must be declared

How can I work around this?

Sorry for the dumb question...

Thanks in advance.

Pedro