Jawad,
It looks like you are trying to run Oracle, Enforce, Endpoint Server on a SINGLE CPU with 6GB of RAM???
If so you are trying to do a lot with very little resource.
Couple of things to do is see what RAM you have allocated to the Endpoint Server (VontuMonitor.conf check the heap size) you would want this to be a min of 512 and max of 1024.
Also look at the Drive IO.. you may be taxing this server pretty well with Disk IO. This is what can be causing the issuse..
When you modofy the policy is it processed by the UI and then written to the DB and then pushed to the Endpoint Server where it is then processed into memory. This is a lot of writes and memory changes, so you are doing a lot with very little RAM resources.
I would try to increase the RAM.
What version of Oracle are you running?
Is this a VM??
Ronak