[Kmail] access permissions and owners:group for ~/Mail/.xxx/.xx.sorted

[Gerhard Gaußling]

Hello All,

I migrated my emails from debian sarge to ubuntu horay amd64.
Now I got issues with file permissions and/or users/group of *.sorted 
files in $HOME/Mail/...

kmail: WARNING: Error: Failure 
modifying /home/gerhard/Mail/.Maillists.directory/.users at beonex.org.index.sorted 
(No space left on device?)
kmail: WARNING: /build/buildd/kdepim-3.4.0/kmail/kmheaders.cpp:3227

Which permission groups/user should such file have on ubuntu horay 
amd64?

Help is much appreciate.

Kind regards

Gerhard Gaußling