Ok, I found it:

kwalletmanager does not work, when .trinity/share/apps/kwallet/kdewallet.kwl 
exists prior to the first call of kwalletmanager.

To kwallet work again, I had to 
remove .trinity/share/apps/kwallet/kdewallet.kwl, start kwalletmanager, 
create kwallet.kwl, close kwalletmanager, replace the new created 
kdewallet.kwl with my old backup.

Nik


> I have just reinstalled Debian wheezy (64bit) + TDE (slavecs repository).
>
> The only thing I cannot get to work is kwalletmanager:
> - kwalletmanager is running (icon in systray).
> - klick on icon gives an empty window.
> - "new wallet" does nothing.
>
> So, any idea how I could get this thing working? I would really like to add
> my old wallet.