求助：在vmware esx 4.0中再装虚拟机

我在vmware esx 4.0中装了个xp系统，在这个系统中我再装了个vmware workstation 7.0，然后在vmware workstation 7.0中我想再装系统，就出现错误了。
错误文字如下：
Running VMware Workstation in a virtual machine requires the outer virtual machine to be configured for running a VMware ESX guest operating system. You may not power on a virtual machine until the outer virtual machine is reconfigured.
有知道解决的大侠请告知，不胜感激！