Error:scalac: missing or invalid dependency detected while loading class file 'ActorSystem.class'.

Akka环境：
集成开发环境: IntelliJ IDEA 14.1.5
Scala版本：   scala-sdk-2.11.7
Akka版本: akka-actor_2.11-2.3.14
JDK版本: jdk1.7.0_79


问题：
运行Akka程序时，报错如下：
Error:scalac: missing or invalid dependency detected while loading class file 'ActorSystem.class'.
Could not access term typesafe in package com,
because it (or its dependencies) are missing. Check your build definition for
missing or conflicting dependencies. (Re-run with `-Ylog-classpath` to see the problematic classpath.)
A full rebuild may help if 'ActorSystem.class' was compiled against an incompatible version of com.

解决办法:
    将akka-2.3.14\lib\akka目录下面的config-1.2.1.jar包也配置到工程中, 再次运行就可以了。