field "publication date: " always empty :((

hi gnunet developers
I have a next  problem constantly:
 that I did not try  to insert (add) some file for by the failsharing
utility of gnunet-insert(gnunet-insert file.txt), fields  "publication
date:" remains empty when I search this file with gnunet-search
(gnunet-search -m 1 file.txt). even at application of option of -T, it
is the field is null  (I looked after it both utillizing setup-0.7.0d
and setup-0.7.0b , win xp and win 2000)
What of can it be explained ?  and how to settle it? it only the local
phenomenon ?