Depot validation fails - but which one is broken?

So I tried to check our Backup Vault and it fails after 2 hours with this error:

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Details
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Typ:                         Fehler
Datum und Zeit:              14.09.2011 18:11:55
Backup-Plan:                 [Keine]
Task:                        [Keine]
Typ der verwalteten Einheit: [Keine]
Verwaltete Einheit:          [Keine]
Maschine:                    VEEAM-7
Code:                        4.194.395(0x40005B)
Modul:                       64
Besitzer:                    ASN User
Nachricht:                  
  Validieren von Backup-Archiv 'arl:/6E47449F-1062-412E-A493-3100F11712F0/B50DCA93-6945-4DA6-B651-FD0F1712A96B/D2334855-7C97-4680-85BC-87914FFCEBCA/C5585404-BBE4-435A-B2CA-B7A23D7AA536' vom Speicherort mit ID 'bsp://localhost/CentralLV#arl:/6E47449F-1062-412E-A493-3100F11712F0/B50DCA93-6945-4DA6-B651-FD0F1712A96B' fehlgeschlagen.
Zusätzliche Info:
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Fehlercode: 91
Module: 64
LineInfo: d143f4885f91ef32
Felder:  code : 8
Nachricht: Validieren von Backup-Archiv 'arl:/6E47449F-1062-412E-A493-3100F11712F0/B50DCA93-6945-4DA6-B651-FD0F1712A96B/D2334855-7C97-4680-85BC-87914FFCEBCA/C5585404-BBE4-435A-B2CA-B7A23D7AA536' vom Speicherort mit ID 'bsp://localhost/CentralLV#arl:/6E47449F-1062-412E-A493-3100F11712F0/B50DCA93-6945-4DA6-B651-FD0F1712A96B' fehlgeschlagen.
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Acronis Knowledge Base: http://kb.acronis.com/errorcode

Ereignis-Code: 0x0040005B

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So how do I find out, which backup is broken? How do I translate those GUIDs in something I can delete and then (possibly) recreate? And as this is a deduplicating Storage Node: How do I see how many backups are affected by this problem?

And finally: What is causing this and how do I prevent this from happening. I'm using Build 17217, Codename Beta - but that's all I have.

I already filed a support request and I'm waiting for a reaction there too...