Error running 'sbt start-device'

I'm trying to get set-up with sbt and the sbt android-plugin on Mac OS 10.6.6. I installed all of the files and am able to launch the Android SDK manager from the command line. The android-plugin will create an sbt project.

However, when I try to run sbt start-device, I get the following error:

Error running aapt-generate: java.lang.RuntimeExcep开发者_如何学JAVAtion: You need to set ANDROID_SDK_HOME or ANDROID_SDK_ROOT or ANDROID_HOME

But if I run echo $ANDROID_HOME, I get /Users/paul/opt/android-sdk-mac_x86

And the android-sdk-mac_x86/tools folder is in my path. What gives?

Ok, you set $ANDROID_HOME, but have you exported it?