GWT service error

I am passing two parameters to my service which are String arrays. I am getting the following exception.

Please help!

dashletDataService: An IncompatibleRemoteServiceException was thrown while processing this call.

com.google.gwt.user.client.rpc.IncompatibleRemoteServiceException: java.lang.ClassNotFoundException: num_active_queries

at com.google.gwt.user.server.rpc.RPC.decodeRequest(RPC.java:323)

at com.google.gwt.user.server.rpc.RemoteServiceServlet.processCall(RemoteServiceServlet.java:206)

at com.google.gwt.user.server.rpc.RemoteServiceServlet.processPost(RemoteServiceServlet.java:248)

at com.google.gwt.user.server.rpc.AbstractRemoteServiceServlet.doPost(AbstractRemoteServiceServlet.java:62)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:637)

at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)

at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:487)

at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:362)

at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)

at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:181)

at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:729)

at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:405)

at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)

at org.mortbay.jetty.handler.RequestLogHandler.handle(RequestLogHandler.java:49)

at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)

at org.mortbay.jetty.Server.handle(Server.java:324)

at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:505)

at org.mortbay.jetty.HttpConnection$RequestHandler.content(HttpConnection.java:843)

at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:647)

at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:205)

at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:380)

at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:395)

at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:488)

Caused by: com.google.gwt.user.client.rpc.SerializationException: java.lang.ClassNotFoundException: num_active_queries

at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamReader.deserialize(ServerSerializationStreamReader.java:683)

at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamReader.readObject(ServerSerializationStreamReader.java:567)

at com.google.gwt.user.server.rpc.core.java.util.Map_ServerCustomFieldSerializerBase.deserialize(Map_ServerCustomFieldSerializerBase.java:37)

at com.google.gwt.user.server.rpc.core.java.util.HashMap_ServerCustomFieldSerializer.deserialize(HashMap_ServerCustomFieldSerializer.java:40)

at com.google.gwt.user.server.rpc.core.java.util.HashMap_ServerCustomFieldSerializer.deserializeInstance(HashMap_ServerCustomFieldSerializer.java:54)

at com.google.gwt.user.server.rpc.core.java.util.HashMap_ServerCustomFieldSerializer.deserializeInstance(HashMap_ServerCustomFieldSerializer.java:33)

at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamReader.deserializeImpl(ServerSerializationStreamReader.java:859)

at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamReader.deserialize(ServerSerializationStreamReader.java:662)

at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamReader.readObject(ServerSerializationStreamReader.java:567)

at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamReader$ValueReader$8.readValue(ServerSerializationStreamReader.java:140)

at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamReader.deserializeValue(ServerSerializationStreamReader.java:425)

at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamReader.deserializeClass(ServerSerializationStreamReader.java:807)

at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamReader.deserializeImpl(ServerSerializationStreamReader.java:878)

at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamReader.deserialize(ServerSerializationStreamReader.java:662)

at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamReader.readObject(ServerSerializationStreamReader.java:567)

at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamReader$ValueReader$8.readValue(ServerSerializationStreamReader.java:140)

at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamReader.deserializeValue(ServerSerializationStreamReader.java:425)

at com.google.gwt.user.server.rpc.RPC.decodeRequest(RPC.java:312)

... 22 more

Caused by: java.lang.ClassNotFoundException: num_active_queries

at java.lang.ClassLoader.findClass(Unknown Source)

at java.lang.ClassLoader.loadClass(Unknown Source)

at java.lang.ClassLoader.loadClass(Unknown Source)

at org.mortbay.jetty.webapp.WebAppClassLoader.loadClass(WebAppClassLoader.java:352)

at org.mortbay.jetty.webapp.WebAppClassLoader.loadClass(WebAppClassLoader.java:337)

at java.lang.Class.forName0(Native Method)

at java.lang.Class.forName(Unknown Source)

at com.google.gwt.user.server.rpc.impl.ServerSerializationStreamReader.deserialize(ServerSerializationStreamReader.java:609)