If you are getting errors “Pass phrase incorrect” in your apache logs on Snow Leopard server, it is because the key is protected by a password. I found the answer here.
The password for the key is stored in the System Keychain. It is a password entry called “Mac OS X Server certificate management”. You can open the entry and select “Show Password”. You may also use the security command line tool to dump the password.
security find-generic-password -l "Mac OS X Server certificate management" -g
security dump-keychain -d # look in data for password which will look like a GUID
Once you have the password, you can create a copy of the key without the password using openssl:
openssl rsa -in /etc/certificates/server.domain.com.uniqueid.key.pem \ -out /etc/certificates/server.domain.com.uniqueid.passwordlesskey.pem
You can then replace the password protected key with the passwordless key or point apache to the passwordless key in your /etc/apache2/sites/sitename.conf file.