First ROOT THAT THING!!! And backup your efs folder.
Then change your CSC to something properly.
The old 1.5 Kies was reported not working (somehow blocked via Sammy so you have to use the new one). So your only way is spoofing the new one (which I heard didnt work, just showed the new FW didnt allow to install) or to change the CSC.
Couple of things.
First what rom you have?
3 button recovery/download?
Did you apply any lagfix?
Dont do any of this till you reply to my questions!
Rooting with super one click root. This should be relatively safe even if you did something stupid before.
Backup efs folder so you dont loose your imei , this is kinda crucial as it happens from to time(on what you are about to do) and since you bought in europe you would be literaly f.cked :P . (after root use sgs tools or toolbox, whatever is in market) and send the backup to your PC, USB, mail wherever is safe, not just your phone.
If you dont wanna go custom and keep the stock. Well choose the best CSC you would like what would fit you. and check if it also has already froyo 2.2.1 good page is http://www.samfirmware.com/
(I changed mine which was IRD and changed it to XEU as that having updates sooner) . since I have no idea which rom you have, it might even work with that old code which is in SGS toolbox /tools or you use the automatic one from the thread you posted in the first post, the method wiht the IMEI and code.
Anyway dont forget to answer the questions before you do anything. So you dont end up with a useless brick