I have been trying for 4 days to get app-engine and grails working together on my mac to no avail. I am using latest groovy/grails and appengine sdk versions. Im following the app-engine plugin step by step on the grails site..
http://grails.org/plugin/app-engine

Groovy Version: 1.7.1 JVM: 1.5.0_22
Grails 1.3.0.RC1
echo $APPENGINE_HOME reveals
/Users/markstim/appengine-java-sdk-1.3.2

I perform the following steps
1. grails create-app myapp
2. cd myapp; grails list-plugins reveals
hibernate 1.3.0.RC1 -- Hibernate for Grails
tomcat 1.3.0.RC1 -- Apache Tomcat plugin for Grails
add the following line to Config.groovy
google.appengine.application="myapp"
install the plugin for app-engine grails install-plugin app-engine and answer 'jpa' when asked (no errors yet)

installed plugins list now looks like
app-engine 0.8.9 -- Grails AppEngine plugin
gorm-jpa 0.7.1 -- GORM-JPA Plugin
then grails run-app and get this error as the server is coming up...

[java] WARNING: Nested in org.springframework.beans.factory.BeanCreationException: 

Error creating bean with name 'pluginManager' defined in ServletContext 

resource [/WEB-INF/applicationContext.xml]: 

Invocation of init method failed; nested exception is 

org.codehaus.groovy.grails.exceptions.NewInstanceCreationException: 

Could not create a new instance of class [GormJpaGrailsPlugin]!:
     [java] java.lang.NoClassDefFoundError: org.grails.jpa.JpaPluginSupport

then if i navigate to localhost:8080 I get

HTTP ERROR: 503

Problem accessing /myapp. Reason:

SERVICE_UNAVAILABLE

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