"VirtualBox - Critical Error" When VMs are Runned From Scheduled Tasks

I have 2 VMs running with VirtualBox under a Windows 2003 Server R2 Standard x64 Edition, both are started with scheduled tasks when server starts.

VMs:

1. Debian x64
2. Windows XP Professional

Both works normaly, but I can't manage them when I log into the server, when I try to run any application of VirtualBox (VboxManage.exe, VirtualBox.exe, VBoxHeadless.exe and etc.) I got:

Failed to create the VirtualBox COM object.
The application will now terminate.
Callee RC: CO_E_SERVER_EXEC_FAILURE (0x80080005)

At the taskmanager I see 3 processes from VirtualBox:

Image Name / User Name

VBoxHeadless.exe / SYSTEM

VBoxHeadless.exe / SYSTEM

VBoxSVC.exe / SYSTEM

I already tried to run with my user (it's in administrator group of Active Directory) and I got the same results.

When I kill the VBoxSVC.exe I can run the other commands again, but the other VMs dies, and I have to kill both VBoxHeadless process to have the VMs running again.

I've been searching for a while, but until now I wasn't able to succeeded.

In Windows 7 64-bit, deleting the associated .VirtualBox file worked for me.