error:"

You Do Not Have Sufficient Permission To Write To Folder Forums/UserAvatar/

Running IIS 7.0 on server 2008, application  pool wsc, as I understand it I must asign wsc full rights to folder and sub folders of website, correct ?
When trying to assign permissions wsc "doesn't exist"
NETWORK SERVICE has full rights already.
What am I doing wrong?

Still cannot find wsc , Here is entire senerio:
Created on Windows 7(not on domain) machine downloaded with MS platform installer(basically setup everything)
Transferred to Server 2008 and IIS 7.0 by coping folder and setting up IIS manually(appeared to work till tried to add avatar), I did not create a domain account as write up I was reading simply stated to make sure network service had full rights to folder and sub folders. Is this where I went wrong?

If so how can I correct?

Could I have use vs2010 to publish Site? 

Creating an account and using  wright up at http://msdn.microsoft.com/en-us/library/ff649309.aspx I am now able to work with site pictures and avatars.

As a side note also I found that I was using asp.net 4.0(oN iis 7.0), changed to 2.0(APP running 3.5) and everything now works.

LEARNED ALOT , THANKS FOR YOUR HELP