[horde] Groupware - You must configure a DataTree backend to use Shares.

[Ross Lindsay]

Hi!
I am attempting to install Horde Groupware on a 1&1 Shared Server, and I get

"You must configure a DataTree backend to use Shares."
as an error message when I go to mydomain.com/horde.
The full message is
"*Warning*: array_merge()
[function.array-merge<http://rmliv.com/horde/services/portal/function.array-merge>]:
Argument #1 is not an array in *
/homepages/37/d204637238/htdocs/horde/turba/config/sources.php* on line *201
*
A fatal error has occurred - You must configure a DataTree backend to use
Shares.
[line 47 of
/homepages/37/d204637238/htdocs/horde/lib/Horde/Share/datatree.php]"
When I click on "Add content", I get "
*Warning*: array_merge()
[function.array-merge<http://rmliv.com/horde/services/portal/function.array-merge>]:
Argument #1 is not an array in *
/homepages/37/d204637238/htdocs/horde/turba/config/sources.php* on line *201".

*What is wrong and what do I need to do to fix it?

Thanks!
Ross