Acronis B&R 11.5: scheduled backup hanging indefinitevly

Hi.

I have a scheduled incremental backup that every now and then does not complete after 3 days running properly, so I find it hanging at the console.

I'm looking at the details of the activity, stuck at 75%, the last message is "Command 'Backing Up' completed successfully'. Clicking STOP makes the job complete with errors after 9 hours. The client is online and working properly. Please help me interpret the error log:

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Log Entry Details
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Type: Warning
Date and time: 29/09/2014 10:49:40
Backup plan: PC1_Daily
Task: Incremental backup
Managed entity type: [None]
Managed entity: [None]
Machine: PC1.net
Code: 20.250.684(0x135003C)
Module: 309
Owner:
Message:
Command 'Running backup plan 'PC1_Daily'' has completed with warnings.
Additional info:
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Error code: 60
Module: 309
LineInfo: 4a8728dc8a1c950b
Fields: $module : mms_vs_32308
Message: Command 'Running backup plan 'PC1_Daily'' has completed with warnings.
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Error code: 41
Module: 307
LineInfo: e6792a5ee190dda7
Fields: $module : agent_protection_addon_vs_32308
Message: ProtectCommand: Failed to execute the command.
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Error code: 11
Module: 373
LineInfo: dfd7515541030d07
Fields: $module : staging_command_addon_vs_32308
Message: Failed to resolve the secondary location. Location: 'PC1\Acronis\'; Archive: 'PC1.net_D_Archive'.
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Error code: 50
Module: 309
LineInfo: 8d165e86fb819563
Fields: $module : mms_vs_32308
Message: The activity has been canceled.
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Error code: 203
Module: 161
LineInfo: b320396adfe3b9a
Fields: IsReturnCode : 1, $module : disk_bundle_vs_32308
Message: Failed to get information about the backups.
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Error code: 3
Module: 143
LineInfo: 9a79f20828bcb38
Fields: IsReturnCode : 1, $module : disk_bundle_vs_32308
Message: The running task has been canceled.
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