my ipod 4th gen won't update to the new one with imessage and all that.

I got my ipod touch in march 2011. So its not ios 5. But everytime i plug it in this is what happens step by step.

1. Itunes comes up like usual and asks me if i want to updated my ipod to 5.0.1.

2. The tag your pictures come up.

3.I tag the pitures and say ok to the updating.

4. the sound comes up to say that my pics are uploaded.

5.it contacts the apple people.

6.it says the are some pucheses that haven`t been transefed. but i click continue

7.it says that it will restore and backup.(update too)

8.it starts backing it up.

9. it says and error occurered while backing it up.(-43) but i hit update anyways and continue

10. its says that it cant be restored because the ipod cannot be found.

it never axctually gets to the state of updating. in wont restore. I have tried updating itunes to 10.5 and putting the iopod into recovery mode. when i put it into reconvery mode and plug it back in, itunes says you have to restore it. i hit restore but then itunes says it cant and then the ipod is sunddenly normal again, like it was never put into recovery mode.