超级头疼的EJB错误啊！

我用MyEclipse7.0+weblogic9.2开发EJB应用程序
总是出现下面的问题：javax.naming.NamingException: String index out of range: -1
at weblogic.jndi.Environment.getContext(Environment.java:300)
at weblogic.jndi.Environment.getContext(Environment.java:277)
at weblogic.jndi.WLInitialContextFactory.getInitialContext(WLInitialContextFactory.java:117)
at javax.naming.spi.NamingManager.getInitialContext(Unknown Source)
at javax.naming.InitialContext.getDefaultInitCtx(Unknown Source)
at javax.naming.InitialContext.init(Unknown Source)
at javax.naming.InitialContext.<init>(Unknown Source)
at com.ejb.EJBTest.main(EJBTest.java:26)客户端测试代码如下：
package com.ejb;
import java.rmi.RemoteException;
import java.util.Properties;import javax.ejb.CreateException;
import javax.naming.Context;
import javax.naming.InitialContext;
import javax.naming.NamingException;
import com.interfaces.HelloWorld;
import com.interfaces.HelloWorldHome;public class EJBTest {   /**
   * @param args
    */
    public static void main(String[] args) {
        // TODO 自动生成方法存根
      Properties properties=new Properties();
         properties.setProperty(Context.INITIAL_CONTEXT_FACTORY,"weblogic.jndi.WLInitialContextFactory");
         properties.setProperty(Context.PROVIDER_URL,"192.168.1.100");
   
        Context context;
         try {
            context = new InitialContext(properties);
            HelloWorldHome home=(HelloWorldHome)context.lookup("HelloWorld");
            HelloWorld hw=home.create();
            String s=hw.hello();
            System.out.println(s);
         } catch (NamingException e) {
             // TODO 自动生成 catch 块
            e.printStackTrace();
        } catch (RemoteException e) {
            // TODO 自动生成 catch 块
            e.printStackTrace();
        } catch (CreateException e) {
            // TODO 自动生成 catch 块
            e.printStackTrace();
           }
       }
}