Error: Could not convert variant of type (Null) into type...

I am getting the following error in my log file for SQL Backup:

Error: Could not convert variant of type (Null) into type (Int64)

My backup job is failing with exitcode 500. Here's the relevant events and logs:

Job step output:

Executed as user: 3NET\SQLServerService. FULL_(local)_Eor_20060927_004500.sqb [SQLSTATE 01000] (Message 0) SQL Backup job failed with exitcode: 500 SQL error code: 0 [SQLSTATE 42000] (Error 50000). The step failed.


Events:

3455 :
Analysis of database 'Eor' (7) is 100% complete (approximately 0 more seconds)

18267 :
Database restored: Database: Eor, creation date(time): 2005/06/10(11:15:16), first LSN: 48675:47337:1, last LSN: 48675:47359:1, number of dump devices: 1, device information: (FILE=1, TYPE=VIRTUAL_DEVICE: {'SQLBACKUP_D5850EF7-FD9B-4931-92A3-25C017E4DA37'}).


Logs:

SQL Backup log file
9/28/2006 3:01:30 AM: Reading file header of "F:\MSSQL\Backup\Eor\FULL_(local)_Eor_20060927_004500.sqb"

9/28/2006 3:01:30 AM: RESTORE HEADERONLY FROM DISK = 'F:\MSSQL\Backup\Eor\FULL_(local)_Eor_20060927_004500.sqb'

9/28/2006 3:02:16 AM: Error: Could not convert variant of type (Null) into type (Int64)


SQL Backup log file
9/28/2006 3:02:17 AM: Restoring Eor (database) from:
F:\MSSQL\Backup\Eor\FULL_(local)_Eor_20060927_004500.sqb

9/28/2006 3:02:17 AM: RESTORE DATABASE [Eor] FROM DISK = 'F:\MSSQL\Backup\Eor\FULL_(local)_Eor_20060927_004500.sqb' WITH RECOVERY, MOVE 'Eor_Data' TO 'f:\MSSQL\Data\Eor_Data.mdf', MOVE 'Eor_Log' TO 'c:\Program Files\Microsoft SQL Server\MSSQL\Data\Eor_Log.ldf', REPLACE

Processed 246696 pages for database 'Eor', file 'Eor_Data' on file 1.
Processed 2 pages for database 'Eor', file 'Eor_Log' on file 1.
RESTORE DATABASE successfully processed 246698 pages in 78.234 seconds (25.832 MB/sec).


Thanks for any help.