JBoss error MSC00001: Failed to start service jboss.deployment.unit, what does it mean ? java.lang.ClassNotFoundException

hi,

   I have the following error in JBoss and don't know for what reason we have it and what does it mean, anyone can help ? :

12:12:51,702 ERROR [org.jboss.msc.service.fail] (MSC service thread 1-1) MSC00001: Failed to start service jboss.deployment.unit."bpm.war".POST_MODULE: org.jboss.msc.service.StartException in service jboss.deployment.unit."bpm.war".POST_MODULE: Failed to process phase POST_MODULE of deployment "bpm.war"
      at org.jboss.as.server.deployment.DeploymentUnitPhaseService.start(DeploymentUnitPhaseService.java:119) [jboss-as-server-7.1.1.Final.jar:7.1.1.Final]
      at org.jboss.msc.service.ServiceControllerImpl$StartTask.startService(ServiceControllerImpl.java:1811) [jboss-msc-1.0.2.GA.jar:1.0.2.GA]
      at org.jboss.msc.service.ServiceControllerImpl$StartTask.run(ServiceControllerImpl.java:1746) [jboss-msc-1.0.2.GA.jar:1.0.2.GA]
      at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source) [rt.jar:1.7.0_80]
      at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source) [rt.jar:1.7.0_80]
      at java.lang.Thread.run(Unknown Source) [rt.jar:1.7.0_80]
Caused by: java.lang.RuntimeException: Error getting reflective information for class com.hds.hub.api.processes.impl.WFManagerImpl with ClassLoader ModuleClassLoader for Module "deployment.bpm.war:main" from Service Module Loader
      at org.jboss.as.server.deployment.reflect.DeploymentReflectionIndex.getClassIndex(DeploymentReflectionIndex.java:70) [jboss-as-server-7.1.1.Final.jar:7.1.1.Final]
      at org.jboss.as.ee.metadata.MethodAnnotationAggregator.runtimeAnnotationInformation(MethodAnnotationAggregator.java:58)
      at org.jboss.as.ee.component.deployers.InterceptorAnnotationProcessor.handleAnnotations(InterceptorAnnotationProcessor.java:85)
      at org.jboss.as.ee.component.deployers.InterceptorAnnotationProcessor.processComponentConfig(InterceptorAnnotationProcessor.java:70)
      at org.jboss.as.ee.component.deployers.InterceptorAnnotationProcessor.deploy(InterceptorAnnotationProcessor.java:55)
      at org.jboss.as.server.deployment.DeploymentUnitPhaseService.start(DeploymentUnitPhaseService.java:113) [jboss-as-server-7.1.1.Final.jar:7.1.1.Final]
      ... 5 more
Caused by: java.lang.NoClassDefFoundError: Lcom/hds/web/bpm/sessions/EnvironmentProvider;
      at java.lang.Class.getDeclaredFields0(Native Method) [rt.jar:1.7.0_80]
      at java.lang.Class.privateGetDeclaredFields(Unknown Source) [rt.jar:1.7.0_80]
      at java.lang.Class.getDeclaredFields(Unknown Source) [rt.jar:1.7.0_80]
      at org.jboss.as.server.deployment.reflect.ClassReflectionIndex.<init>(ClassReflectionIndex.java:57) [jboss-as-server-7.1.1.Final.jar:7.1.1.Final]
      at org.jboss.as.server.deployment.reflect.DeploymentReflectionIndex.getClassIndex(DeploymentReflectionIndex.java:66) [jboss-as-server-7.1.1.Final.jar:7.1.1.Final]
      ... 10 more
Caused by: java.lang.ClassNotFoundException: com.hds.web.bpm.sessions.EnvironmentProvider from [Module "deployment.bpm.war:main" from Service Module Loader]
      at org.jboss.modules.ModuleClassLoader.findClass(ModuleClassLoader.java:190)
      at org.jboss.modules.ConcurrentClassLoader.performLoadClassUnchecked(ConcurrentClassLoader.java:468)
      at org.jboss.modules.ConcurrentClassLoader.performLoadClassChecked(ConcurrentClassLoader.java:456)
      at org.jboss.modules.ConcurrentClassLoader.performLoadClass(ConcurrentClassLoader.java:398)
      at org.jboss.modules.ConcurrentClassLoader.loadClass(ConcurrentClassLoader.java:120)
      ... 15 more

12:12:51,736 INFO  [org.jboss.as.server] (DeploymentScanner-threads - 1) JBAS015870: Deploy of deployment "bpm.war" was rolled back with failure message {"JBAS014671: Failed services" => {"jboss.deployment.unit.\"bpm.war\".POST_MODULE" => "org.jboss.msc.service.StartException in service jboss.deployment.unit.\"bpm.war\".POST_MODULE: Failed to process phase POST_MODULE of deployment \"bpm.war\""}}
12:12:51,752 INFO  [org.jboss.as.server.deployment] (MSC service thread 1-6) JBAS015877: Stopped deployment bpm.war in 14ms


bpm.war is deployed and EnvironmentProvider is present in the war so why the ClassNotFoundException ?