Problem while installing Plugins

[eligu]

Playing around with Alitheia-Core, getting the source code, importing it to Eclipse and so on, while I executed alitheia core (through m2e mvn pax:provision), it could't install the plugin at Plugin tab. The message I got was:
ERROR - No plug-in implements metric Wc.loc which is required by Module size metrics
ERROR - Plug-in installation failed.
After making a clean install and changing the default DB to MySql and running from cmd I keept getting the same problem. Performing two or more restart, then it started to install the plugins (I verified it in MySql), however the problem was occasionally appearing, after that. Below is a snapshot of the logs at the moment the problem was happening:

ERROR - No plug-in implements metric Wc.loc which is required by Module size metrics
ERROR - Plug-in installation failed
ERROR - Can not modify property (CMF_threshold) for plugin (Developer Contribution
ERROR - null: eu.sqooss.service.pa.PluginInfo.addConfigEntry(PluginInfo.java:384) eu.sqooss.service.abstractmetric.AbstractMetric.addConfigEntry(AbstractMetric.java:748) eu.sqooss.metrics.contrib.ContributionMetricImpl.install(ContributionMetricImpl.java:108) eu.sqooss.impl.service.pa.PAServiceImpl.installPlugin(PAServiceImpl.java:463) eu.sqooss.impl.service.pa.PAServiceImpl.installPlugin(PAServiceImpl.java:436) eu.sqooss.impl.service.webadmin.PluginsView.render(PluginsView.java:163) sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) java.lang.reflect.Method.invoke(Method.java:606) org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl.doInvoke(UberspectImpl.java:389) org.apache.velocity.util.introspection.UberspectImpl$VelMethodImpl.invoke(UberspectImpl.java:378) org.apache.velocity.runtime.parser.node.ASTMethod.execute(ASTMethod.java:270) org.apache.velocity.runtime.parser.node.ASTReference.execute(ASTReference.java:252) org.apache.velocity.runtime.parser.node.ASTReference.render(ASTReference.java:339) org.apache.velocity.runtime.parser.node.SimpleNode.render(SimpleNode.java:336) org.apache.velocity.Template.merge(Template.java:328) org.apache.velocity.Template.merge(Template.java:235) eu.sqooss.impl.service.webadmin.AdminServlet.sendPage(AdminServlet.java:295) eu.sqooss.impl.service.webadmin.AdminServlet.doGet(AdminServlet.java:196) eu.sqooss.impl.service.webadmin.AdminServlet.doPost(AdminServlet.java:233) javax.servlet.http.HttpServlet.service(HttpServlet.java:727) javax.servlet.http.HttpServlet.service(HttpServlet.java:820) org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:502) org.mortbay.jetty.servlet.OsgiServletHolder.handle(OsgiServletHolder.java:101) org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:363) org.mortbay.jetty.servlet.OsgiServletHandler.handle(OsgiServletHandler.java:117) org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:181) org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:766) org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152) org.mortbay.jetty.Server.handle(Server.java:324) org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:534) org.mortbay.jetty.HttpConnection$RequestHandler.content(HttpConnection.java:879) org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:741) org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:213) org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:403) org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:409) org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:522)
ERROR - No plug-in implements metric EMCC_TOTAL which is required by Maintainability Index
ERROR - Plug-in installation failed
ERROR - No plug-in implements metric ISSRCMOD which is required by Maintainability Index
ERROR - Plug-in installation failed
ERROR - No plug-in implements metric ISSRCMOD which is required by Maintainability Index
ERROR - Plug-in installation failed

EDIT: Probably this is not an Alitheia-Core issue. After looking at the code, I see that, when installing a metric plugin, if that plugin has a dependency declared at annotation level (@MetricDecl) than the dependency must be installed first. However, I think there is no way how can user understand which module requires which, in our case we can see it by the code, at least I didn't find any.