errors and messages are not displaying using form_set_error() method and drupal_set_message()

Hello,

I am using form_api for making a form to validate and submit some info in the database, but I am not getting the error messages or success messages after submitting the data into db. It is validating the form and submitting the form properly, but not showing any message in the page. Can anybody tell me the possible issues?

Regards,
Braham