Your build looks like it's failing because it can't find apt, which is a new tool included in JDK 1.5. You might need to add your JAVA_HOME/bin directory to your path before starting IntelliJ.
I'm not sure how IntelliJ's Ant integration interacts with the system environment variables, the JDK you're using to run IntelliJ, and the JDK you've configured IntelliJ to use for the CPAS project.
You could also try to build from the command line. Try running "ant build" from the <cpas-root>/modules directory. You'll need JDK 1.5 and Ant on your path.
error.log