Horde sql charset error

[Price,Neil]

I get this error in my logs:

--------
Oct 10 12:25:01 HORDE [emergency] [horde] Required "charset" not specified
in horde configuration.

The file /etc/horde/horde3/../config/conf.php should contain a
$conf['sql']['params']['charset'] setting.
--------

My database is set to "none" in Horde (I'm assuming I don't need mysql when
using Horde with Kolab)

If I add the setting manually it gets wiped out on the next config change. 

Do I simply ignore the error or am I supposed to be using a database?
Apologies if this is a really stupid question.

Horde version is 3.3