Fails to delete older backups [also fails to run program after backup]

Acronis 11.5 update 5 build 39029 (latest build right now) running on Windows 2008 doesn't delete the old backups.

The error log is below:

1 Information 1/22/2015 8:00:01 PM Command 'Running backup plan 'Daily backup of server2 to \\serverdc\server2backup$\'' is running.
2 Information 1/22/2015 8:00:06 PM Command 'Backing up' is running.
3 Information 1/22/2015 8:00:20 PM Analyzing partition '1-0'...
4 Information 1/22/2015 8:00:21 PM Create Full Backup
From: Disk '1'
To file: "file://serverdc\server2backup$\server2_2015_01_22_20_00_19_628D.TIB"
Compression: None
Exclude: Files matching mask
Match criterion: *.tib, *\System Volume Information\*{3808876B-C176-4e48-B7AE-04046E6CC752}; ...
Ask for the first media: No

5 Information 1/22/2015 8:00:21 PM Pending operation 155 started: 'Creating partition image (No label ())'.
6 Information 1/22/2015 8:00:21 PM Locking partition 1-1...
7 Information 1/22/2015 8:00:22 PM Pending operation 155 started: 'Creating partition image (No label (C))'.
8 Information 1/22/2015 8:00:33 PM Locking partition C:...
9 Information 1/22/2015 8:21:35 PM Pending operation 152 started: 'Saving partition structure (Hard disk 1)'.
10 Information 1/22/2015 8:21:42 PM Command 'Backing up' has completed successfully.
11 Information 1/22/2015 8:22:07 PM Command 'Replicating backups/cleaning up archives (1st location)' is running.
12 Error 1/22/2015 8:24:55 PM Command 'Replicating backups/cleaning up archives (1st location)' has failed.
Additional info:
--------------------
Error code: 61
Module: 309
LineInfo: 4a8728dc8a1c950f
Fields: $module : service_process_vs_39029
Message: Command 'Replicating backups/cleaning up archives (1st location)' has failed.
--------------------
Error code: 218
Module: 161
LineInfo: b320396adfe3ccb
Fields: IsReturnCode : 1, $module : disk_bundle_vs_39029
Message: Failed to delete the backups from archive '\\serverdc\server2backup$\#arl:/33C1756A-6848-435E-9B8C-2B0CD0A16C3D/7C586C0F-205C-41DF-B4D6-720798F3F233/460989D5-3AAF-4B80-81C6-E779E41DDD41?archive_name%3dserver2' by the specified filter.
--------------------
Error code: 507
Module: 64
LineInfo: a1d3981537c687bf
Fields: id : server2_2015_01_20_09_27_45_318D.TIB, $module : disk_bundle_vs_39029
Message: Failed to open the backup archive by the ID.
--------------------
Error code: 1
Module: 64
LineInfo: 98130db273d2480
Fields: $module : disk_bundle_vs_39029
Message: The archive is invalid or its type is unsupported.
--------------------
Error code: 9
Module: 64
LineInfo: 95962d9a14426d33
Fields: $module : disk_bundle_vs_39029
Message: Failed to find the backup.
--------------------
Error code: 9
Module: 64
LineInfo: 95962d9a14426d33
Fields: $module : disk_bundle_vs_39029
Message: Failed to find the backup.
--------------------
Task 'Full backup' has failed on machine 'server2.Domain.local'.

As a workaround, I am running the batch file below after a backup (backup options, pre/post commands) to delete old ones, and it never finishes, but it runs fine when I run the batch file from explorer. When I click "test command", I see a CMD window with mms.exe running. After waiting 30 seconds, I close mms.exe (it should only take ten seconds to run), and get the attached acronis.xml error, which doesn't mention anything related to the batch file or mms.exe.

Here's the error when running the batch file:

-----------------------------------------------------------------
Error
-----------------------------------------------------------------
Failed to execute the user command.
-----------------------------------------------------------------
Details:
Code: 1,024(0x00000400)
LineInfo: 0x858CC05F488A8DCC;

Module: mms_vs_39029
Message: Child process has exited with code '-1,073,741,510'.

-----------------------------------------------------------------

Here's the batch file

net use x: "\\serverdc\server2backup$"
forfile -p "x:" /m *.tib -d 10 -c "cmd /c del echo @file"
sleep 15
net use x: /d /y
exit /B 0

I found this article that mentions to just close the window.

To summarize, I have two questions:

How do I get Acronis to delete old backups?

Do the pre/post command run only after a successful backup? Or do they always run?