Updating over the air (OTA), i.e. via wifi or 3G, is known to be unreliable. To update the firmware, do it via a pc (aka flashing). Look at the Wiki and post back if you get stuck, with the line of the Wiki you don't get/have problem with.

Re CSSU: Again, read the Wiki and post with the thing you don't get (not "can't install cssu" in a new thread).

Re: Kernel-Power: mmm. Do some reading on this first!

Good luck.