iCal and Mail don't work after downgrade from Lion to Snow Leopard

Hey everyone, after an extremely awful time with with Lion (it knocked out of my audio interface AND my wireless) I downgraded back to Snow Leopard yesterday. I made a Carbon Copy of my Lion drive with all my data on an external drive (which I still have) and after wiping my local drive clean I reinstalled Snow Leopard from my disk. After it was done I chose to transfer data from another system local system (I selected everything) and an hour and a half later everything was transferred over. After doing a software update, I've found that I get big error messages with iCal, Mail, and even the App Store that say they can't open and I'm assuming that it has to do with incompatible data that got transferred from Lion. Any ideas on how to get those programs back up and running?? Thanks so much for you help!

Luke

ps. here's the error message from iCal

Dyld Error Message:

Symbol not found: _kSecOIDX509V1ValidityNotAfter

Referenced from: /System/Library/PrivateFrameworks/ApplePushService.framework/Versions/A/ApplePu shService

Expected in: /System/Library/Frameworks/Security.framework/Versions/A/Security

in /System/Library/PrivateFrameworks/ApplePushService.framework/Versions/A/ApplePu shService