cannot get/add folder 'discussion_threads' to parent id: 0

[blueBoy]

Hi Janos,

    i hope you are in good health.
When i try to re-run pilerimport second time with same cmdline, i get
following errors
for example:
 pilerimport    -c /usr/local/etc/piler.conf -R -F zipper-a -d zipper-a
cannot get/add folder 'discussion_threads' to parent id: 0
   After i update some mails in folder i need to rerun pilerimport for
processing  extra mails, then it shoots the  above error.
I have tried above on many folders.

Thanks.
Blue Boy.