Data translation doesn't want to stay

[vsese]

We need a german translation of Cyclos under "vsese.ch".
Now, if I translated the phrase under "Data Translation" (Datenübersetzung) -> "Password Type" (Passwort Typ) from
"Please enter your password below. This password is used to login to the system. The password should contain at least 4 characters and have a maximum of 12 characters."
to
"Bitte geben Sie unten Ihr Passwort ein. Dieses Passwort wird verwendet, um sich beim System anzumelden. Das Passwort sollte mindestens 4 Zeichen und maximal 12 Zeichen enthalten."
and the word "Birth date" to "Geburtsdatum", found under "Data Translation" (Datenübersetzung) -> "Profile fields" (Profilfelder)
then this translations stay a few hours but then they are resetted to the english version.
This translations were used in the registration form and we have much persons that didn't understand English.
Please correct that bug! Thank you in advance.