OK, make a folder called "GT I9100"
Save the Odin and fw files to the folder. Extract the fw file once only, to the same folder, you will get one file called I9100XWLPT_I9100XXLQ6_I9100XEULPA_HOME.tar.md5.
extract the flasher and pit file. This will give you the odin prog and the pit file.
Open odin and click on the box that says "Pit". A box will open for you to search for the pit file, so navigate to your folder called GT I9100 and double click on the pit file you just extracted and it will load into the box. Do the same for the "PDA" box, and load in the .tar.md5 file.
Connect your cable and wait fir the drivers to install and the comms box to go yellow, then hit start and wait 5 mins....