Warning: Cannot modify header information - headers already sent by (output started at....

Ok, i'm getting an error message at the bottom of every single one of my pages. the error contains:

Warning: Cannot modify header information - headers already sent by (output started at /home/irwin/www/www/includes/common.inc:2561) in drupal_send_headers() (line 1040 of /home/irwin/www/www/includes/bootstrap.inc).
PDOException: SQLSTATE[42S02]: Base table or view not found: 1146 Table 'irwin_drupal.field_data_field_body' doesn't exist: SELECT field_data_field_body0.entity_type AS entity_type, field_data_field_body0.entity_id AS entity_id, field_data_field_body0.revision_id AS revision_id, field_data_field_body0.bundle AS bundle FROM {field_data_field_body} field_data_field_body0 WHERE (field_data_field_body0.deleted = :db_condition_placeholder_0) AND (field_data_field_body0.bundle = :db_condition_placeholder_1) LIMIT 10 OFFSET 0; Array ( [:db_condition_placeholder_0] => 1 [:db_condition_placeholder_1] => webform ) in field_sql_storage_field_storage_query() (line 569 of /home/irwin/www/www/modules/field/modules/field_sql_storage/field_sql_storage.module).