sqlserver user which is used in asp.net programming is not having the permission to execute the RECONFIGURE statement.
create a new user, login with the new user and use it in asp.net.
use the following snippet to create new user
use master;
go
drop login TestUser;
go
create login TestUser with password = '';
USE <yourdatabase>;
drop user TestUser;
create user TestUser for login TestUser with default_schema = dbo;
go
setuser 'TestUser'
go
exec sp_configure 'allow updates', 1
RECONFIGURE
go
setuser
</yourdatabase>