I have this iphone sent to me and when I put in an etisalat Sim to set it up, I get the following message "The Sim card that you currently have installed in this iphone is from a carrier that is not supprotedunder the activation policy that is currently assigned by the activation server. this is not a hardware issue with the iphone. please insert another sim card from a supported carrier or request that this iphone be unlocked by your carrier. please contact apple for more information."
How can this be resolved please? As send Said phone had been unlocked.

Sure , contact me, my number in my signature

Dear Op, you need to do a SIM UNLOCK for the phone.. its been lockd to a carrier prob. 'cos d phone was bought on contract. try vistn an engineer that can do that for U.

If you have a US sim card or network supported sim card, just insert it to active it and you can start using any other sim on it.

Did you resolve the issue? Similar problem here. Unlock services in naija claim it is locked, but it really isn't. In my case, I had already activated it with a US SIM.
From my research the particular model of this iphone has restrictions to carriers with certain bands. Still, it should work in Etisalat(9 mobile) which has a 4G band of 3 -- but it didn't.