Unable to activate iTunes after jail-breaking iPhone?

I have jailbroken my iPhone 4 and it has the latest version of IOS on it.
I have backed it up with iCloud and now I want to join it onto iTunes but the message that comes up is; 'There's no SIM card installed in the iPhone you are attempting to activate.' So it does not let me see the data on it and put music on it.

You can activate easily by the following these points…
1. Check your iTunes installation.
2. Plug your device into your computer.
3. Disable your iOS device screen lock.
4. Find your iOS version. There are different methods of jailbreaking depending on which version of iOS your device is running. To find your version:
Open Settings on your device.
Select General.
Tap About.
Your version number will be displayed under the '''Version''' heading.
There's currently no way to jailbreak an iOS device running 6.1.3 untethered. Untethered means that the device does not need to be connected to the computer every time that you turn it on. To perform a tethered jailbreak, follow the method listed lower in this guide.

Bellow points can help you to activate…
* Connect the iPhone to USB

* Hold the power button on your iPhone and 'slide to power off'

* Open redsn0w (run as administrator if using Windows)

* Click 'Extras' -> 'Select ipsw'

* Choose the 6.0 ipsw (NOT the 6.1.3 version)

* Choose 'yes' on the box that pops up (unless it's an old-bootrom 3GS)

* Click 'Back'

* Click 'Jailbreak'

* If none of the options are checked/selected then redsn0w will jailbreak and hactivate the iPhone. (If you want the Cydia bundle to be included along with that, then leave only the "Install Cydia" option checked/selected.)

* When asked if you are sure you want to proceed, click 'yes'
Follow the DFU instructions