ASP .NET Web Site Administration Tool Problem

Hi,
I have a problem when I use ASP .NET Web Application Administration tool. When I click the Security tab, I receive following message
"There is a problem with your selected data store. This can be caused by an
invalid server name or credentials, or by insufficient permission. It can also
be caused by the role manager feature not being enabled. Click the button below
to be redirected to a page where you can choose a new data store.

The following message may
help in diagnosing the problem: Unable to connect to SQL Server database."
In the same page, there is a button to go to Provider section. I clicked it, and I went to the Provider page. There, there were two links, which were: "Select a single
provider for all site management data" and
"Select a different provider for each feature
(advanced)". I clicked the earlier, and I was redirected to a page to select provider. There, there was a link, I clicked it and I receive following message:
"
Provider
Management

Could
not establish a connection to the database.
If you have not yet created the
SQL Server database, exit the Web Site Administration tool, use the
aspnet_regsql command-line utility to create and configure the database, and
then return to this tool to set the provider.
"
After reading this message, I opened Command Prompt and went to C:WINDOWSMicrosoft.NETFrameworkv2.0.50727. There, I ran the aspnet_regsql command, and then ASP .NET SQL Server Setup Wizard was displayed. In the first page of this wizard I chose "Configure SQL Server for application services" and then I clicked "Next" button. In the second page I left all fields as they were and then I clicke"Next". In the third page I only clicked "Next" and then some process ran. Finally, in the last page I received following message:
"
Setup failed.

Exception:
Unable to connect to SQL Server database.

----------------------------------------
Details of failure
----------------------------------------

System.Web.HttpException: Unable to connect to SQL Server database. ---> System.Data.SqlClient.SqlException: An error has occurred while establishing a connection to the server.  When connecting to SQL Server 2005, this failure may be caused by the fact that under the default settings SQL Server does not allow remote connections. (provider: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server)
   at System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection)
   at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj)
   at System.Data.SqlClient.TdsParser.Connect(ServerInfo serverInfo, SqlInternalConnectionTds connHandler, Boolean ignoreSniOpenTimeout, Int64 timerExpire, Boolean encrypt, Boolean trustServerCert, Boolean integratedSecurity, SqlConnection owningObject)
   at System.Data.SqlClient.SqlInternalConnectionTds.AttemptOneLogin(ServerInfo serverInfo, String newPassword, Boolean ignoreSniOpenTimeout, Int64 timerExpire, SqlConnection owningObject)
   at System.Data.SqlClient.SqlInternalConnectionTds.LoginNoFailover(String host, String newPassword, Boolean redirectedUserInstance, SqlConnection owningObject, SqlConnectionString connectionOptions, Int64 timerStart)
   at System.Data.SqlClient.SqlInternalConnectionTds.OpenLoginEnlist(SqlConnection owningObject, SqlConnectionString connectionOptions, String newPassword, Boolean redirectedUserInstance)
   at System.Data.SqlClient.SqlInternalConnectionTds..ctor(DbConnectionPoolIdentity identity, SqlConnectionString connectionOptions, Object providerInfo, String newPassword, SqlConnection owningObject, Boolean redirectedUserInstance)
   at System.Data.SqlClient.SqlConnectionFactory.CreateConnection(DbConnectionOptions options, Object poolGroupProviderInfo, DbConnectionPool pool, DbConnection owningConnection)
   at System.Data.ProviderBase.DbConnectionFactory.CreatePooledConnection(DbConnection owningConnection, DbConnectionPool pool, DbConnectionOptions options)
   at System.Data.ProviderBase.DbConnectionPool.CreateObject(DbConnection owningObject)
   at System.Data.ProviderBase.DbConnectionPool.UserCreateRequest(DbConnection owningObject)
   at System.Data.ProviderBase.DbConnectionPool.GetConnection(DbConnection owningObject)
   at System.Data.ProviderBase.DbConnectionFactory.GetConnection(DbConnection owningConnection)
   at System.Data.ProviderBase.DbConnectionClosed.OpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory)
   at System.Data.SqlClient.SqlConnection.Open()
   at System.Web.Management.SqlServices.GetSqlConnection(String server, String user, String password, Boolean trusted, String connectionString)
   --- End of inner exception stack trace ---
   at System.Web.Management.SqlServices.GetSqlConnection(String server, String user, String password, Boolean trusted, String connectionString)
   at System.Web.Management.SqlServices.SetupApplicationServices(String server, String user, String password, Boolean trusted, String connectionString, String database, String dbFileName, SqlFeatures features, Boolean install)
   at System.Web.Management.SqlServices.Install(String database, SqlFeatures features, String connectionString)
   at System.Web.Management.ConfirmPanel.Execute()
"
What should I do? I tried to use this administration tool on computer in my house and everything was just fine. Why do I have this problem in my office?