Failed to determine temporary file name. Error code: 267

Hello

Acronis (version 10 update 3) is running in this case on SBS 2008, backup going to Buffalo Live Station NAS drive, I have already cleared temporary files under Windows\Temp and SPECIFIEDUSER\AppData\Local\Temp and on C have 100GB free space. It ran before but for some reason stopped working. There is another backup going to USB hard disk, running fine.

Log is:

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Log Entry Details
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Type: Error
Date and time: 01/02/2013 10:16:09
Backup plan: NAS
Task: Differential backup
Code: 66,590(0x1041E)
Module: 1
Owner: iliadadmin@ILIAD
Message:
Failed to determine temporary file name. Error code: 267.
Acronis Knowledge Base: http://kb.acronis.com/errorcode/

Event code:

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and after:

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Log Entry Details
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Type: Error
Date and time: 01/02/2013 10:16:14
Backup plan: NAS
Task: Differential backup
Code: 11,863,304(0xB50508)
Module: 181
Owner: /HIDDEN/
Message:
Task 'Differential backup' failed: 'Error occurred while running the backup and recovery engine.
Additional info:
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Error code: 2
Module: 218
LineInfo: 600f7166ce397df5
Fields: $module : C:\Program Files (x86)\Acronis\BackupAndRecovery\mms.exe
Message: Error occurred while running the backup and recovery engine.
--------------------'.
Acronis Knowledge Base: http://kb.acronis.com/errorcode/

Event code: 0x00DA0002

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Please give some advise how to fix this issue.