Without some additional information very difficult to determine. ie: My car will not start, and there's plenty of petrol.
The I at the end of the code indicate that the message is informational.
What is the full text of the message?
What were the messages leading up to the ANS0266I messgae?
With the os, are there any error message(s)?
Did the message occur during a schedule backup? or a manual backup? or a restore?
On the TSM Server were there any message(s) around the time frame of when the ANS0266I message occur?
Good Luck,
Sias