ABR11 Backup failed

See error below,
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Log Entry Details
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Type: Error
Date and time: 4/01/2012 11:22:09 AM
Backup plan: [None]
Task: [None]
Code: 20,250,627(0x1350003)
Module: 309
Owner: root
Message:
Command 'Backing up' has failed.
Additional info:
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Error code: 3
Module: 309
LineInfo: 4a8728dc8a1c94f8
Fields:
Message: Command 'Backing up' has failed.
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Error code: 32834
Module: 114
LineInfo: c35c04057128fd60
Fields:
Message: Virtual machine backup has failed.
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Error code: 32853
Module: 114
LineInfo: c35c04057128fd95
Fields:
Message: Not all virtual machines have been backed up.
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Error code: 32852
Module: 114
LineInfo: c35c04057128fdda
Fields:
Message: Failed to back up virtual machine 'PSA'.
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Error code: 72
Module: 161
LineInfo: d26f78546258519c
Fields: IsReturnCode : 1
Message: Failed to lock the object.
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Acronis Knowledge Base: http://kb.acronis.com/errorcode/

Event code: 0x01350003+0x00728042+0x00728055+0x00728054+0x00A10048

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