[horde] Another "DataTree backend" problem - but during setup process

[Wojtek]

Hello,

I'm trying to run "Horde Groupware Webmail Edition 1.2.9", but I keep 
getting:

You must configure a DataTree backend to use Shares.
[line 47 of .../horde/lib/Horde/Share/datatree.php]

I was looking through internet and I could only find that the problem is 
connected with some mistakes in configuration process. However in my 
case this error appears during setup process. I run:

/horde/admin/setup/

and when I try tu run Horde configuration (Horde (horde) 3.3.11) I get 
the above error. There is also some satus warning:

No version found in your configuration. Regenerate configuration.

All the other configurations run well:

Dynamic Mail (dimp) H3 (1.1.6), Filtry (ingo) H3 (1.2.5), Kalendarz 
(kronolith) H3 (2.3.5), Książka adresowa (turba) H3 (2.3.5), Mobile Mail 
(mimp) H3 (1.1.3), Poczta (imp) H3 (4.3.9), Uwagi (mnemo) H3 (2.2.4), 
Zadania (nag) H3 (2.3.6)
[some names are in polish]

also /horde/test.php doesn't show any problems. Does anybody have an 
idea what am I doing wrong?

Thank you in advance,
Wojtek Jurewicz