MySQL Errors with Formidable Forms

Can’t use this plugin when Formidable (Pro) is enabled:

[Not unique table/alias: 'ham_postmeta']<br /><code>SELECT SQL_CALC_FOUND_ROWS DISTINCT ham_posts.ID FROM ham_posts  LEFT JOIN ham_postmeta ON (ham_posts.ID = ham_postmeta.post_id AND ham_postmeta.meta_key = '_frm_temporary' )  LEFT JOIN ham_postmeta AS mt1 ON (ham_posts.ID = mt1.post_id AND mt1.meta_key = '_frm_file' ) LEFT JOIN ham_postmeta ON ham_posts.ID = ham_postmeta.post_id  LEFT JOIN ham_postmeta AS sq1 ON ( ham_posts.ID = sq1.post_id AND sq1.meta_key = '_wp_attached_file' ) WHERE 1=1  AND ( 
  ( 
    ham_postmeta.post_id IS NULL 
    AND 
    mt1.post_id IS NULL
  )
) AND ham_posts.post_type = 'attachment' AND ((ham_posts.post_status = 'inherit' OR ham_posts.post_status = 'private'))AND ID IN (-1) GROUP BY ham_posts.ID ORDER BY ham_posts.post_date DESC LIMIT 0, 200

i browsed code by _frm_temporary and this is what i found:

/**
	 * Set _frm_temporary and _frm_file metas
	 * to use for media library filtering
	 */
	private static function add_meta_to_media( $media_ids, $type = 'temporary' ) {
		foreach ( (array) $media_ids as $media_id ) {
			if ( is_numeric( $media_id ) ) {
				update_post_meta( $media_id, '_frm_' . $type, 1 );
			}
		}
	}

	/**
	 * When an entry is saved, remove the temp flag
	 */
	private static function remove_meta_from_media( $media_ids ) {
		foreach ( (array) $media_ids as $media_id ) {
			if ( is_numeric( $media_id ) ) {
				delete_post_meta( $media_id, '_frm_temporary' );
			}
		}
	}

public static function filter_media_library( $query ) {
		if ( 'attachment' == $query->get( 'post_type' ) ) {
			$meta_query = $query->get( 'meta_query' );
			self::query_to_exclude_files( $meta_query );

			$query->set( 'meta_query', $meta_query );
		}
	}
private static function query_to_exclude_files( &$meta_query ) {
		if ( current_user_can( 'frm_edit_entries' ) ) {
			$show = FrmAppHelper::get_param( 'frm-attachment-filter', '', 'get', 'absint' );
		} else {
			$show = false;
		}

		if ( ! is_array( $meta_query ) ) {
			$meta_query = array();
		} else {
			$continue = self::nest_attachment_query( $meta_query );
			if ( ! $continue ) {
				return;
			}
		}

		$meta_query[] = array(
			'relation' => 'AND',
			array(
				'key'     => '_frm_temporary',
				'compare' => 'NOT EXISTS',
			),
			array(
				'key'     => '_frm_file',
				'compare' => $show ? 'EXISTS' : 'NOT EXISTS',
			),
		);
	}

add_action( 'pre_get_posts', 'FrmProFileField::filter_media_library', 99 );

hope this helps to fix the error!