File Backup Fail - (0x40001) & (0x40019)

I have setup an one time file backup (full) in an effort to duplicate important files contained on one external USB drive (Seagate 4TB) to another external USB drive (Seagate 5TB) for the purpose of redundancy. Validation is not a chosen option.
The backup starts then soon after fails for a reasons I cannot discern.

Here is what is in the event log:
Error occurred while backing up. (0x40019)
Tag = 0xCE542E14DA203B82
Error occurred while reading the file. (0x40001)
Tag = 0x32C603B262BDB593

All files are accessible and readable on the source drive and the target drive is nearly empty and readable.
The computer is a Dell Precision T3500 with a 6 core Xeon (W3680), 12 gb RAM, and a fresh install of Win 7 Pro x64.
Any help would be greatly appreciated.
Let me know if more information is needed...
TIA!