Ok it doesnt sound like you are doing it wrong, but I will try with some instructions to make it completely fool-proof. Some of the steps are likely to be unnecessary but this way will leave you in no doubt.
- Do a factory reset and full wipe + cache and dalvik.
- Flash a GB rootable ROM with PC-Odin. DO NOT USE A NANDROID.
Root it with zergrush exploit.
- See this thread for stock ROMs and rooting method:
http://xdaforums.com/showthread.php?t=1329360
- Do a factory reset and full wipe + cache and dalvik.
- Download Mobile Odin Pro
- Re-download CF-Repack from here: http://www.mirorii.com/fichier/3/501208/I9220LP1-N7000-ICS-REPACK-tar.html and put on your external SD card.
- Re-download SGN0T from the OP and put on your external SD card
- Flash the CF Root .tar with Mobile Odin Pro (make sure Everroot, CWM etc are all ticked - they are normally ticked by default)
- Once finished the phone should automatically boot in to CWM. DO NOT REBOOT THE PHONE!
- Do a factory reset and full wipe + cache and dalvik.
- Immediately install SGN0T in CWM.
- Do a factory reset and full wipe + cache and dalvik.
- Reboot your phone and you should be fully set with a baseband.