Error message after upgrade

[torbjorn . m . granlund]

After I upgraded emacs from 22.3 to 25.1 I get an error message each time I 
send an email with gnus. I've tried to understand the problem but have failed 
after several hours of work.

The error message is:

  nndraft:drafts..~ error: Can’t select group (no such directory): drafts..~

I don't ever set any vriable to the zany valeu "drafts..~".

Please help. Messages seem to be sent, but this error message is quite annoying.