Please check this article: http://blog.sqlauthority.com/2008/02/19/sql-server-2005-fix-error-message-when-you-run-a-query-against-a-table-that-does-not-have-a-clustered-index-in-sql-server-2005-a-severe-error-occurred-on-the-current-command/
Hope it will help you to resolve your issue..
SQL Database Recovery Expert 🙂