Internal error in library. The linked position is unknown

Acronis online backup has become unreliable. The latest email notification is as follows. I would be grateful for insight. Also, is there a way to wipe out my online backup and start again?

1 Information 1/6/2012 10:16:57 PM Online Backup
2 Information 1/6/2012 10:16:57 PM Operation Online Backup started manually.
3 Information 1/6/2012 10:16:57 PM Analyzing partition '0-0'...
4 Information 1/6/2012 10:16:58 PM Analyzing partition '1-1'...
5 Information 1/6/2012 10:16:58 PM Analyzing partition '1-2'...
6 Information 1/6/2012 10:16:58 PM Analyzing partition 'C:'...
7 Information 1/6/2012 10:16:58 PM Online Backup
8 Information 1/6/2012 10:17:26 PM Trying to set shared lock to the file stream.
9 Information 1/6/2012 10:17:27 PM Shared lock is not supported by the file stream.
10 Information 1/6/2012 10:18:40 PM Locking partition C:...
11 Acronis True Image Home 1/6/2012 11:03:10 PM Internal error in library. The linked position is unknown.
12 Information 1/6/2012 11:09:17 PM Resending an upload request: attempt number 0.
13 Information 1/6/2012 11:15:53 PM Resending an upload request: attempt number 1.
14 Information 1/6/2012 11:22:14 PM Resending an upload request: attempt number 2.
15 Information 1/6/2012 11:28:43 PM Resending an upload request: attempt number 3.
16 Information 1/6/2012 11:35:02 PM Resending an upload request: attempt number 4.
17 Information 1/6/2012 11:42:06 PM Resending an upload request: attempt number 5.
18 Information 1/6/2012 11:48:52 PM Resending an upload request: attempt number 6.
19 Information 1/6/2012 11:55:30 PM Resending an upload request: attempt number 7.
20 Information 1/7/2012 12:01:57 AM Resending an upload request: attempt number 8.
21 Information 1/7/2012 12:08:34 AM Resending an upload request: attempt number 9.
22 Warning 1/7/2012 7:58:31 AM Canceled.
23 Warning 1/7/2012 7:58:31 AM Canceled.
24 Information 1/7/2012 7:58:34 AM Trying to unlock the file stream.
25 Information 1/7/2012 7:58:34 AM Unlocking is not supported by the file stream.
26 Warning 1/7/2012 7:58:35 AM Operation has been stopped.
27 Warning 1/7/2012 7:58:35 AM Internal error in library. The linked position is unknown.
28 Acronis True Image Home 1/7/2012 7:58:37 AM Operation has completed with errors.