Permissons für Active Directory Account to run IIS Application Pool

I've a .NET 2.0 Application running on IIS. I need an Active Directory Account to run the IIS Application pool, it's not possible to use NETWORK SERVICE or LOCAL SYSTEM.

I got the following errormessage, if I try to connect to the application:
Application pop-up: w3wp.exe - Application Error : The instruction at "0x73585d55" referenced memory at "0x00000018". The memory could not be "read"."

Normally this becomes because the IIS Application Pool Account NETWORK SERVICE has not the right permissons on HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\ASP.NET_2.0.50727\Names (more information in: (Thread: Application popup: w3wp.exe - Application Error )

I gave my Active Directory Account, i use for IIS AppPool the same permissons on this regkey, but this does not works for meh. What could be the problem in my case? Do I have to give somewhere elas permissons for this account. (Account is in local Administrators group)

Thx a lot
sandsturm