Error Creating Deployment 有关Tomcat配置问题，请高手帮忙！

Myeclipse配置Tomcat的时候出现提示框
The selected server is enabled,but is not configured properly.Deployment to it will not be permitted until the problem is corrected. Please navigate to the server prefence pages and verify the field with the prompt:Tomcat JDK name
怎么样解决啊？希望详细说明一下~~~~谢谢了！

Error creating object. %%%% Error Creating SessionFactory %%%% 我玩绿宝石386（电脑）没法保存，回弹出Error creating file(null), 电脑不停地弹出一连串的框框,上面有"error creating window device context" ，这是怎么回事? 在解压sql server 2005为何弹出包含Error creating file: "．．．．"错误的对话框， 我刚重装了系统,为什么窗口最小化时会出现creating directx3d error 的对话框,点击确定后窗口会关闭? failed creating the direct3D device Failed creating the Direct3D device.什么意思？ Failed creating the Direct3D device是什么意思 鬼武者3“Failed creating the Direct3D device ”