I can't install iTunes 10 on my computer!!

When I'm installing it, there's a windows that says "there's is a problem with the windows installer package you are using. there's a program that is needed to this instalation be completed", so I don't know what I can do to install iTunes 10, and I need it because I just bought an iPhone 4 but I can not sync it with my music!

My computer uses Windows XP, 32 bit, service pack 2!