The current identity does not have write access to 'C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files

I resolved this issue by installing aspnet_regiis -i . But my problem is , it happends frequently , Whenever we get this error we use aspnet_regiis -i this command .
I gone throw many articles but I did not get any permanent solution of this problem. I have given full access to asp .net temporary file. There is no ISS Buffer Overflow Exploit Prevention problem.
I am using Windowes Server 2003 / IIS 6 / ASP.Net 3.5
Please help me .