Hi Eric,
Ok, I managed to power On an additional machine once I increased my CPU allocation (The allocation I set was over the total size of my capacity) and vCPU speed, decreased the CPU resources guaranteed for vm's as you recommended.
My machine where I'm doing my testing doesn't have a lot of recourses , it is Intel i5 2.67 Ghz + 8 GM memory machine. On my primary host I have 2 vCenter machines, one for the primary host and one for the vCD, I have also vShiled manager + vCD + ESXi host for vCD.
vCenter1(primary) - 280 Mhz 781 MB (XP machine) it is a 4.1 ESXi.
vCenter2 (for vCD) - 140 Mhz 2 GB
vCD - 196Mhz 1.56GB
vShield- 168 Mhz 631 MB
Esxi (nested) - 1.12 Ghz 1.15 GB
I will try to increase the number of CPU in my nested ESXi (vCD host), it may help in my performance.
I appreiate your effrot and help.