Actually I had this problem last night when I installed it on my XP desktop.
I did a few things to get it to work, though I dont know what did it, so heres basically what I did.
Uninstall spore creature creator, uninstall the download manager, reinstall spore, tell no to the installation to the download manager. When starting up the program, leave the mouse alone till it gets to the main screen with the galaxy in the background.
Anyway thats what fixed it for me.