IPhone 3G error 1015 after 4.1 restored?

Some kind of an error occurred while I was updating my iPhone 3G to 4.2.1. So it asked me to restore my iPhone. And I did it. But I can't restore it either via iTunes because it says "Error 1050".

Whenever I connect my iPhone to my computer it says my iPhone is in recovery mode and ask to restore it. I tried to restore it several times but it won't work. Now I can't switch on my iPhone.

What should I do?

Get root the Custom Firmware