Access denied error while creating sub directory inside the directory.

Hi Guys,
I am facing one problem while creating the subdirectory inside a directory.The error message shown is **'Access to the path 'tempimages' is denied.**'
I have given full access permission to some of the user accounts in the drive where directory is to be created via application.
Now in the global.asax i have registered one method which will allow the above user accounts to create a directory.I am able to create parent directory after assigning the access rule for the user accounts.
But when i try to create the subdirectory inside that directory using the same access rules.I get the above error.

string useraccountForDirectoryCreate = System.Environment.UserDomainName;
dacl.AddAccessRule(new System.Security.AccessControl.FileSystemAccessRule(useraccountForDirectoryCreate,
System.Security.AccessControl.FileSystemRights.FullControl,
System.Security.AccessControl.InheritanceFlags.ContainerInherit |
System.Securit ...