American Greetings Creatacard is a great old program.
Unfortunately, it just isn't compatible with anything new.
The software developers (Broderbund) have done nothing to stay up to date with new versions of Windows.
I know people that like it enough that they use a dual boot setup with an old copy of WinXP 32bit. Use Windows 7 for every day stuff. Bootup in WinXP when you need to make a card (or run other older software).
Dual Boot Installation with Windows 7 and XP
http://www.sevenforums.com/tutorials/8057-dual-boot-installation-windows-7-xp.html