Nokia 6120C and phonebook names display problem.

You can read about this problem on many forums

One is this.

http://discussions.europe.nokia.com/t5/Nseries-Devices-and-S60/Nokia-6120c-or-many-S60-phones-messaging-and-reflecting/m-p/354063

You have contacts on your phonebook and the name is not displayed when
you get a call/sms. You have no duplicated entries on the phonebook.

This is how I solved it. I don't know if some/all of the steps are
necessary, but you will get an idea.

1. It was on v.3 and I reseted it completelly (you have to intro a
code while booting up). That didn't resolve the problem.

2. Then upgraded to v.6. Still with problem.

3. The number It had problems to display was my own number. There was
no duplicated entry on the phonebook but I found a contact called "Int
voice mail" which had this similarity:

"My number" +countrycode851xxxxx
"Int voice mail" +countrycode8551xxxxx

The only difference was that extra 5. If I call that number I get a
message saying that I have tried to call myself.

How did I find it? I deleted my own number's contact and then I called
myself. That contact appeared.

4. After I deleted that contact, the problem has disappeared.

---- Recommendation:
Upgrade (see nokia website)
Check duplicated/similar phone numbers
Reset completely if nothing else solve the problem.

Hope it helps someone.