Join Date:Joined: Aug 2010
You need to have rooted your phone AND replaced the ROM with a Gingerbread ROM before attempting to change the theme. If you don't understand what I just said, you have a lot of reading to do. Start with the thread in Streak 5 General titled "Everything You Always Wanted To Know About The Streak But Were Too Busy Bricking It".
P.S. It wasn't necessary to quote the entire message.