Task Error Message

I've just upgraded to TI2010 build 7160. I've started to see this error message when my task starts. An hour later I get another email saying the task started and completed successfully.

1 Error 9/3/2013 2:00:01 AM No such script '1986F7E4-2D60-406F-9CFE-F8176C226C9E'.
2 Warning 9/3/2013 2:00:02 AM Failed to process pair script:1986F7E4-2D60-406F-9CFE-F8176C226C9E.
3 Error 9/3/2013 2:00:02 AM Operation has completed with errors.

This seems to be happening on all of my tasks, and when I check the log files this error does not seem to be associated with any particular task. I've attached a screenshot of the logs. You can see that prior to my scheduled task, another unscripted task starts a few seconds before, doesn't complete and then I get this error. Then the scheduled task starts and completes fine. What does this mean?

Thanks.