i dont know why it has to be emailed (its kinda like whats the point in sending cofirm msg to email when you sign up to a site . you know you are cofirming it thats why you are signing up ).. you have no need to be concerened....
never do you have to buy an unlock code (EVER) THIS IS 100%FREE
goldcard is for bypassing ruu spl cid checks so you can downgrade or root .. you especially need a goldcard if you are on 3uk on 1.5 and on a stock ROM .. im not sure but i think everyother network you dont need a GC its just 3 patched the ROM . but there maybe cases of needing one on other networks (you'll have to ask someone who has more experience than me )
a goldcard is to help in the rooting process for people like me on 3 network .. there is another way to make goldcard which is like walking 200miles when you could drive , its quick and convienient
akiramar got it working on xp so maybe send him msg asking how he done it and got it working .. as the goldcard states only tested on vista and 7 , but people have got it working on xp
why are you trying to Goldcard . are you trying to get root . what version are you on . still 1.5 or 2.1
edit : just been searching and that error is something to do with NET framework...
here is link to get it, its for xp sp2
http://www.microsoft.com/downloads/...58-915b-4eb5-9b1d-10e506da9d0f&displaylang=en. when you download and install wait half hour and run windows updates to see if a newer version is available, there probably is im on vista and on 3.5 framework . but 4 is coming out soon .. not sure if its same on xp , once installed try using the tool again if it dont work run windows update to see if there is a newer version and try that