[Tech] Delete failed on bucket xxxx errors

[Mr. Flibble]

Hi guys,
On freenet 0.5, what does this error mean:

(freenet.support.FileBucket, Finalizer, ERROR): Delete failed on bucket
t7869b6b6

I've had quite a few with various numbers at the end a few minutes ago.
Should I be concerned?

Thanks,

MrFlibble