carrier, network, operator, mobile service provider, cell operator all mean *almost* the same thing so don't worry about that. Just update your profile to list Orange under the carrier section.
Coming back to your problem now, rueckwaertssuche means reverse search and if your phone came from Orange UK shouldn't be there. So where did you get the phone from?
Your phone has either been registered at some point on a corporate system ( that BES thingy the other user was talking about) and has leftovers on the menus, or you have installed either a mapping (gps, location, postcode) application, or a contacts management app that has non english menus. Those are the only cases this word makes sense that i can think of.
If that's an Orange branded handset you can pop into an Orange shop, tell them "the future's bright" and would be even brighter if they could take away the germans that are invading your blackberry.
If you want to do the dirty deed yourself you can download software specific to your blackberry (Bold/9000) and your carrier (Orange/UK) from here: https://www.blackberry.com/Downloads...223C61B1B5AB89
I would suggest since you seem to be inexperienced with the platform to go over the FAQ before you attempt software upgrades. Talking directly to Orange is also a good idea. I believe they charge 20p a pop for the privilege but you can use the mail form in the Orange site to email them.
Help and Support -- Contacting us and then select if you're a contract or a PAYG customer.
Let us know how it goes.