ORA-16014: log string sequence# string not archived, no available destinations
Cause : An attempt was made to archive the named log, but the archive was unsuccessful. The archive failed because there were no archive log destinations specified or all destinations experienced debilitating errors.
Action - How to fix it : DBA Scripts :: www.high-oracle.com/scripts
Verify that archive log destinations are being specified and/or take the necessary step to correct any errors that may have occurred.