Agent unreachable

Hi,

I got some problem with view 4.5

I made linked clones using view composer.

And when I logged in the agent machine, it looks fine.

but after leaving the agent machine for 30 mins without touch, I tried to login that server, I got this error  “This desktop currently has no desktop sources available. Please try connecting to the desktop again later"

and then I checked Events on VMware View Aministrator. It said that "Agent unreachable"

I ping the server, it worked.

So, I joined the ESX server to see the agent machine. When I looked the console of the agent machine, It was like stuck.

After rebooting the agent machine, It worked fine.

But after leaving the agent mahcine for 30 mins without touch , the problem happened again.

I don't know why.

I am using below enviroment.

Windows Server 2008 as AD

Windows XP SP3 as Parents machine's snapshot : installed the file ( http://support.microsoft.com/kb/944043/en-us ), joined the domain.