According to the link below, you will need 2.1.4 minimum for Snow Leopard.
http://support.apple.com/kb/TS3021
If you are running an earlier version, then you probably need to contact Apple for verification or decide to upgrade to 3.1.
The other alternative is to stay on the last version of Mac OS X that your version of Aperture ran on successfully.
Unfortunately, this is the price of technology advancement and support costs. 😉