Dear Dnn Guru
I have installed DNN 07.04.02 for almost one year, It's running well. But today the default portal site log is not working. One Child portal site log is still working well. How to fix the problems. The error report is as following:

Error: Site Log is currently unavailable. DotNetNuke.Services.Exceptions.ModuleLoadException: Failed to convert nvarchar value'L'to data type int. ---> System.Data.SqlClient.SqlException: Failed to convert nvarchar value'L'to data type int.at System.Data.SqlClient.SqlConnection. (SqlException exception, Boolean breakConnection, Action`1 wrapCloseInAction) at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj, Boolean callerHasConnectionLock, Boolean asyncClose) at System.Data.SqlClient.TdsParser.TryRun(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj, Boolean& dataReady) at System.Data.SqlClient.SqlDataReader.TryHasMoreRows(Boolean& moreRows) at System.Data.SqlClient.SqlDataReader.TryReadInternal(Boolean setTimeout, Boolean& more) at System.Data.SqlClient.SqlDataReader.Read() at System.Data.Common.DbEnumerator.MoveNext() at Telerik.Web.UI.GridDataTableFromEnumerable.FillData() at Telerik.Web.UI.GridResolveEnumerable.Initialize() at Telerik.Web.UI.GridResolveEnumerable.EnsureInitialized() at Telerik.Web.UI.GridEnumerableFromDataView..ctor(GridTableView owner, IEnumerable enumerable, Boolean CaseSensitive, Boolean autoGenerateColumns, GridColumnCollection presentColumns, String[] additionalField, Boolean retrieveAllFields, Boolean enableSplitHeaderText) at Telerik.Web.UI.GridDataSourceHelper.CreateGridEnumerable(GridTableView owner, IEnumerable enumerable, Boolean caseSensitive, Boolean autoGenerateColumns, GridColumnCollection presentColumns, String[] additionalField, Boolean retrieveAllFields, Boolean enableSplitHeaderText) at Telerik.Web.UI.GridTableView.get_ResolvedDataSource() at Telerik.Web.UI.GridTableView.CreateChildControls(IEnumerable dataSource, Boolean useDataSource) at System.Web.UI.WebControls.CompositeDataBoundControl.PerformDataBinding(IEnumerable data) at System.Web.UI.WebControls.DataBoundControl.OnDataSourceViewSelectCallback(IEnumerable data) at Telerik.Web.UI.GridTableView.PerformSelect() at Telerik.Web.UI.GridTableView.DataBind() at DotNetNuke.Modules.Admin.SiteLog.SiteLog.BindData() at DotNetNuke.Modules.Admin.SiteLog.SiteLog.OnDisplayClick(Object sender, EventArgs e) --- End of inner exception stack trace ---

Dear Mariette Knap

Thank you very much! I delete the records after backup, It's working now.