OK, I have found all the .img files but when I copy the hidden.img file and rename it to hidden.img.tar, I can't put it back into the firmware file again because WinRar doesn't let me.
Ok, what you're doing is NOT what the thread is instructing.
What you need to do is this...
1) Get the hidden.img file... save it to your desktop or where ever.
2) Rename it to hidden.img.tar
3) Insert the hidden.img.tar file into the AP section of ODIN... this is the same section you previously put the md5 file that you were trying to flash
4) Remove the PIT file... not going to use it anymore
5) Remove the check mark from "Re-Partiton"
6) Start ODIN.
Just so you understand... what you're going to do is flash this hidden.img.tar file in ODIN. You are no longer going to flash the md5 file. Make sure you remove the PIT file and do NOT check "Re-Partition"
Hopefully, Odin will complete the flash. This is a cut and paste from that thread....
When the phone boots, the displayed image will be touchwiz teal, there will be a little android and GALAXY spelt above it. Don't freak out.
Give it a minute and it should boot.
Be patient and don't mess with the phone. Give it time like the the quote above states. If the phone boots but goes into a boot loop, you will need to enter recovery and clear/wipe the cache partition and then restart the phone.
I hope this is clearer now, but if you have any question before starting, let me know. However, I'm going to sleep soon, so I won't be monitoring this thread any further tonight.