Come posso fare per interpretare l'errore che mi viene mostrato di seguito?
Le query le ho testate nell'SQL Management Studio e vengono eseguite in pochi secondi senza problemi apparenti, eppure...

codice:
[SqlException (0x80131904): Timeout. Il tempo disponibile è scaduto prima del completamento dell'operazione o il server non risponde.]
   System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection) +2084930
   System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection) +5084668
   System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning() +234
   System.Data.SqlClient.TdsParser.Run(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj) +2275
   System.Data.SqlClient.SqlDataReader.ConsumeMetaData() +33
   System.Data.SqlClient.SqlDataReader.get_MetaData() +86
   System.Data.SqlClient.SqlCommand.FinishExecuteReader(SqlDataReader ds, RunBehavior runBehavior, String resetOptionsString) +311
   System.Data.SqlClient.SqlCommand.RunExecuteReaderTds(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, Boolean async) +987
   System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method, DbAsyncResult result) +162
   System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method) +32
   System.Data.SqlClient.SqlCommand.ExecuteReader(CommandBehavior behavior, String method) +141
   System.Data.SqlClient.SqlCommand.ExecuteDbDataReader(CommandBehavior behavior) +12
   System.Data.Common.DbCommand.System.Data.IDbCommand.ExecuteReader(CommandBehavior behavior) +10
   System.Data.Common.DbDataAdapter.FillInternal(DataSet dataset, DataTable[] datatables, Int32 startRecord, Int32 maxRecords, String srcTable, IDbCommand command, CommandBehavior behavior) +144
   System.Data.Common.DbDataAdapter.Fill(DataSet dataSet, Int32 startRecord, Int32 maxRecords, String srcTable, IDbCommand command, CommandBehavior behavior) +319
   System.Data.Common.DbDataAdapter.Fill(DataSet dataSet, String srcTable) +92
   System.Web.UI.WebControls.SqlDataSourceView.ExecuteSelect(DataSourceSelectArguments arguments) +1618
   System.Web.UI.DataSourceView.Select(DataSourceSelectArguments arguments, DataSourceViewSelectCallback callback) +21
   System.Web.UI.WebControls.DataBoundControl.PerformSelect() +143
   System.Web.UI.WebControls.BaseDataBoundControl.DataBind() +74
   System.Web.UI.WebControls.GridView.DataBind() +4
   System.Web.UI.WebControls.BaseDataBoundControl.EnsureDataBound() +66
   System.Web.UI.WebControls.CompositeDataBoundControl.CreateChildControls() +75
   System.Web.UI.Control.EnsureChildControls() +102
   System.Web.UI.Control.PreRenderRecursiveInternal() +42
   System.Web.UI.Control.PreRenderRecursiveInternal() +175
   System.Web.UI.Control.PreRenderRecursiveInternal() +175
   System.Web.UI.Control.PreRenderRecursiveInternal() +175
   System.Web.UI.Control.PreRenderRecursiveInternal() +175
   System.Web.UI.Control.PreRenderRecursiveInternal() +175
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +2496