Help: Nabble forum scheduled for deletion

[Paul Meems]

I just received this e-mail:
Dear Nabble user:

The forums and posts listed below are inactive and have been scheduled for deletion in 7 days.
To prevent these forums or posts from being deleted, visit the forum or post and follow the instructions.

MapWindow 4
http://n2.nabble.com/MapWindow-4-f3828935.html

Regards,
Nabble Support

I've listed 3 mailing lists. I use them as an archive. The last message of two of them are from today and the other is from Nov. 23
All 3 mailing lists are used a few times a month.

Why are they marked as inactive and how do I prevent them to be deleted?

[Hugo <Nabble>]

Thanks for your feedback. We will adjust our algorithm to be less severe.