5.12.1 activiti modeler

[Lukas]

In my grails application I change activiti plugin version from 5.9 to 5.12.1 and I have problem with runing activiti modeler.
I'm geting:

RestletServlet: [Restlet] ServerServlet couldn't find the target class. Please check that your classpath includes org.activiti.editor.rest.application.ActivitiRestApplication
Message: org.activiti.editor.rest.application.ActivitiRestApplication
    Line | Method
->>  104 | findClass         in org.restlet.engine.util.EngineClassLoader
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 
|    423 | loadClass         in java.lang.ClassLoader
|    356 | loadClass . . . . in     ''
|    231 | loadClass         in org.restlet.engine.Engine
|   1014 | loadClass . . . . in org.restlet.ext.servlet.ServerServlet
|    350 | createApplication in     ''
|    717 | getApplication .  in     ''
|    506 | createServer      in     ''
|    860 | getServer . . . . in     ''
|   1028 | service           in     ''
|   1145 | runWorker . . . . in java.util.concurrent.ThreadPoolExecutor
|    615 | run               in java.util.concurrent.ThreadPoolExecutor$Worker
^    722 | run . . . . . . . in java.lang.Thread

and my build config looks:

dependencies {
        .
        .
        .
        compile ('org.activiti:activiti-engine:5.12.1'){
            excludes 'livetribe-jsr223'
        }
        compile 'org.activiti:activiti-spring:5.12.1'
        compile ('org.activiti:activiti-rest:5.12.1'){
            excludes 'slf4j-log4j12'
        }
        compile 'org.activiti:activiti-modeler:5.12.1'
        compile 'org.activiti:activiti-bpmn-converter:5.12.1'
}

plugins {
        .
        .
        .
        runtime ":spring-security-core:1.2.7.3"
    runtime ":activiti:5.12.1"
    runtime ":activiti-spring-security:0.5.0"
}

How can i run modeler ?