I am having a similar issue. I am using DNN 4.8.1 and SQL EXPRESS 2005. The web.config file has the same connection string for SQL Express and SQL 2000/2005. All the other modules that I am using don't have any connection issues (TEXT/HTML, LINKS, FORM MASTER, SURVEY)
I tried uninstalling the module and downloading the most current version (which was the same) and re-installing but the same error occurs.
<!-- Connection String for SQL Server 2005 Express -->
<add name="SiteSqlServer" connectionString="Data Source=sqlserver.host.com;Initial Catalog=sqldatabase;User ID=myuser;Password=mypassword" providerName="System.Data.SqlClient" />
<!-- Connection String for SQL Server 2000/2005 -->
<add name="SiteSqlServer" connectionString="Data Source=sqlserver.host.com;Initial Catalog=sqldatabase;User ID=myuser;Password=mypassword" providerName="System.Data.SqlClient" />
Error: Media is currently unavailable.
DotNetNuke.Services.Exceptions.ModuleLoadException: 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: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified) ---> 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: SQL Network Interfaces, error: 26 - Error Locating Server/Instance Specified) 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 Microsoft.ApplicationBlocks.Data.SqlHelperParameterCache.DiscoverSpParameterSet(SqlConnection connection, String spName, Boolean includeReturnValueParameter, Object[] parameterValues) at Microsoft.ApplicationBlocks.Data.SqlHelperParameterCache.GetSpParameterSetInternal(SqlConnection connection, String spName, Boolean includeReturnValueParameter) at Microsoft.ApplicationBlocks.Data.SqlHelperParameterCache.GetSpParameterSet(String connectionString, String spName, Boolean includeReturnValueParameter) at Microsoft.ApplicationBlocks.Data.SqlHelperParameterCache.GetSpParameterSet(String connectionString, String spName) at Microsoft.ApplicationBlocks.Data.SqlHelper.ExecuteReader(String connectionString, String spName, Object[] parameterValues) at DotNetNuke.Modules.Media.SqlDataProvider.GetMedia(Int32 moduleId) at DotNetNuke.Modules.Media.MediaController.GetMedia(Int32 moduleID) at DotNetNuke.Modules.Media.MediaModule.Page_Load(Object sender, EventArgs e) --- End of inner exception stack trace ---