Vmware error message while opening any guest OSs !

[Wanas]

When I try to open any Guest OS I got this message

Unable to change virtual machine power state: Cannot find a valid peer process to connect to.

I have tried to create a new guest OS but the same message appear

In the same day I have this message from VMware, Firefox & songbird is so slow in starting, starting in more than a full minute

Is there a way to fix this two problems ?

I am using ubuntu 9.04
Vmware Workstation 6.5.2 build-156735
Firefox 3.5.2 from the daily mozilla builds from the launchpad.com
Songbird the latest

[darco]

Try running this command to see if you have any instances of vmware running:

vmrun list

If you do have vm running the use the vmrun stop command to kill the vm.
Then retry vmware....

darco

[Wanas]

I got it solved
The problem was in installing Avira anti virus
After uninstalling the Avira Guard every thing came back to normal
thanks darco for trying to Help me