Network Share backup fails writing to second tape with error: Fatal error processing children of (4046138)

Date: JUN 2011
Product & Version: NetVault 8.5.3
OS Version: All windows
Symptoms:
Backup starts and runs for a while then when the second tape loads and netvault tries to reopen the data Channel the backup fail with Fatal error processing children of 'xxxxxxxxxxxx'.
As seen in binary log output below:

Information 2011/05/25 10:42:56 355 Schedule Backup-server Starting phase 1 on Backup-server
Job Message 2011/05/25 10:42:57 355 Media Backup-server (Backup-server: d:\Netvault VDL) Job has been assigned media 'Backup-server 23 May 21:15-1' (TQNEK029) in 'DRIVE 1:Backup-server'
Background 2011/05/25 10:42:58 355 Media Backup-server (Backup-server: d:\Netvault VDL) Device 'DRIVE 1:Backup-server' assigned to job,positioning media 'Backup-server 23 May 21:15-1' (TQNEK029) to segment 1
Job Message 2011/05/25 10:42:58 355 Media Backup-server (Backup-server: d:\Netvault VDL) Media in 'DRIVE 1:Backup-server' assigned to job ready for data transfer
Information 2011/05/25 10:42:58 355 Data Plugin Backup-server Connecting to Network Share: \\nl02sanb.area1.eurofins.local\PermanentData
Job Message 2011/05/25 10:50:57 355 Media Backup-server (Backup-server: d:\Netvault VDL) Drive 'DRIVE 1:Backup-server' has completed its transfer


Job Message 2011/05/25 10:50:57 355 Media Backup-server (Backup-server: d:\Netvault VDL) Job has been assigned media 'Backup-server 23 May 21:20-1' (TQNEK044) in 'DRIVE 1:Backup-server'
Background 2011/05/25 10:50:59 355 Media Backup-server (Backup-server: d:\Netvault VDL) Device 'DRIVE 1:Backup-server' assigned to job,positioning media 'Backup-server 23 May 21:20-1' (TQNEK044) to segment 1
Information 2011/05/25 10:50:59 355 Media Backup-server (Backup-server: d:\Netvault VDL) Device 'DRIVE 1:Backup-server' assigned to job succeeded
Job Message 2011/05/25 10:50:59 355 Medi