Cannot Find Symbol Class (BuildServerAdapter, SBuildServer, SRunningBuild, DateBuildNumber)

I'm currently using TeamCity 6.5.

While attempting to learn how plugins are created, I ran into the following compilation error while using IntelliJ

package jetbrains.buildServer.serverSide does not exist
cannot find symbol class BuildServerAdapter
cannot find symbol class SBuildServer
cannot find symbol class SRunningBuild
cannot find symbol class DateBuildNumber

I'm trying to modify this sample posted a while ago by another user: http://confluence.jetbrains.net/display/TW/Date+Build+Number

I have already followed the instructions on setting up the SDKS first using IntelliJ's Project Structure:
1) I created JSDK that points to my JDK 1.6.0.32 installation folder
2) I created IntelliSDK, which uses JSDK (from above) as the Internal Java Platform, as well as added the installation location for IDEA Community Edition 11.1.1 in my Program Files.

Can someone please point me to the right direction? When I try to import jetbrains.buildServer, all I see in there is messages. Many thanks!