Domino Panics with ’Unexpected internal error returned to logger: 0x20762010’ during Backup of Transactional Logs

This issue is documented in APAR # IC60787 where DATA PROTECTION FOR DOMINO BACKUP FAILS WHEN DATABASE IS BUSY BY DOMINO SERVER.  

The fix for this problem is contained in the latest 5.5.3 release of the TDP Domino:
ftp://service.boulder.ibm.com/storage/tivoli-storage-management/maintenance/tivoli-data-protection/domino/Windows/x86_x64/v553/

Relative Technote:

http://www-01.ibm.com/support/docview.wss?rs=669&uid=swg21219345

TDP Domino 5.5.3 also addresses another key issue where TDP Domino may crash on files with local access protection (APAR # IC64849):