[Q] "Not Registered on network" but IMEI Exists and true topic

Hello,
i have updated my mobile to android 4.3 via odin, after update when i come to call any one it gives me "Not registered on network" but my IMEI exists and correct, so what is the reason and how could i fix that ?

this is the software i installed http://www.sammobile.com/firmwares/3/?download=25809

it is for the EMIRATES but i live in EGYPT .. may this be the reason of the problem ??

the egyptian updates has just rolled out http://www.sammobile.com/firmwares/3/?download=26440

should i try to install it ?? and if i did would there be any problems ???????


My About Phone/Status is:

Network: Etisalat
Signal Strength: .... (ok)
Network Type: Edge or HSDPA
Network stete: Out of service............................. ((i think this is the problem))

please help i just bought it from a month
thank you