Sql-server – The ‘SQLNCLI’ provider is not registered on the local machine

I have a NAnt-based script which that I run on my local PC that connects to SQL Server 2008 Express also running on my local PC to drop and recreate databases using .sql files – this works fine, no problem here.

The problem comes when I have recreated the same set-up on another PC, I get the error in my NAnt script saying that:

System.InvalidOperationException: The 'SQLNCLI' provider is not registered on the local machine.
  at System.Data.OleDb.OleDbServicesWrapper.GetDataSource(OleDbConnectionString constr, DataSourceWrapper& datasrcWrapper)
  at System.Data.OleDb.OleDbConnectionInternal..ctor(OleDbConnectionString constr, OleDbConnection connection)
  at System.Data.OleDb.OleDbConnectionFactory.CreateConnection(DbConnectionOptions options, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningObject)
  at System.Data.ProviderBase.DbConnectionFactory.CreateNonPooledConnection(DbConnection owningConnection, DbConnectionPoolGroup poolGroup)
  at System.Data.ProviderBase.DbConnectionFactory.GetConnection(DbConnection owningConnection)
  at System.Data.ProviderBase.DbConnectionClosed.OpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory)
  at System.Data.OleDb.OleDbConnection.Open()
  at NAnt.Contrib.Util.SqlHelper..ctor(String connectionString, Boolean useTransaction)
  at NAnt.Contrib.Tasks.SqlTask.ExecuteTask()
  at NAnt.Core.Task.Execute()
  at NAnt.Core.Target.Execute()
  at NAnt.Core.Project.Execute(String targetName, Boolean forceDependencies)
  at NAnt.Core.Project.Execute()
  at NAnt.Core.Project.Run()

I have searched online and have found that in a forum it was suggested that I needed to install the Microsoft SQL Server Native Client, and got it from this URL. (Admittedly, I have only installed the Native Client part of this)

Despite this being installed on my second PC, the script still gives me the same error. Any suggestions?