It's a harmless error. I'm planning to remove these kinds of errors in a future version.
These occurs when some process deletes or replaces a file between the time that QRecall reads a folder to determine which files need to be captured, and it actually captures the file. If the file has been removed or replaced in the mean time, the OS returns a "file not found" error, QRecall logs it, and moves on.
For files that are contently being replaced (like the iCal preference file in your example), this is fairly typical occurrence. What QRecall needs to do is find out if the file has been replaced with something else and capture that instead, or record that the file has been permanently deleted.
It has no impact on the integrity of the archive.
(any chance you could allow multiple selection and copying directly from the QRecall access version of the log?):
It's already on my to-do list.