First of all you have to download following .jar
spring-security-acl-3.0.2.RELEASE.jar
spring-security-config-3.0.2.RELEASE.jar
spring-security-core-3.0.2.RELEASE.jar
spring-security-taglibs-3.0.2.RELEASE.jar
org.springframework.aop-3.0.2.RELEASE.jar
org.springframework.asm-3.0.2.RELEASE.jar
org.springframework.beans-3.0.2.RELEASE.jar
org.springframework.context-3.0.2.RELEASE.jar
org.springframework.context.support-3.0.2.RELEASE.jar
org.springframework.core-3.0.2.RELEASE.jar
org.springframework.expression-3.0.2.RELEASE.jar
org.springframework.transaction-3.0.2.RELEASE.jar
org.springframework.web-3.0.2.RELEASE.jar
org.springframework.web.servlet-3.0.2.RELEASE.jar
more information here
http://books.zkoss.org/wiki/Small_Talks/2010/April/Making_Spring_Security_Work_with_ZK