Hello Sebestian,
Below is the complete stack trace of error i get when I am trying to add/copy a page.
[ERROR] DotNetNuke.Services.Exceptions.Exceptions - FriendlyMessage="Error: is currently unavailable." ctrl="ASP.desktopmodules_admin_tabs_managetabs_ascx" exc="System.Data.SqlClient.SqlException (0x80131904): Cannot insert duplicate key row in object 'dbo.Tabs' with unique index 'IX_Tabs_PortalLevelParentOrder'. The duplicate key value is (0, 0, <NULL>, 1, 0).
The statement has been terminated.
The 'AddTab' procedure attempted to return a status of NULL, which is not allowed. A status of 0 will be returned instead.
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.TryConsumeMetaData()
at System.Data.SqlClient.SqlDataReader.get_MetaData()
at System.Data.SqlClient.SqlCommand.FinishExecuteReader(SqlDataReader ds, RunBehavior runBehavior, String resetOptionsString)
at System.Data.SqlClient.SqlCommand.RunExecuteReaderTds(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, Boolean async, Int32 timeout, Task& task, Boolean asyncWrite, SqlDataReader ds)
at System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method, TaskCompletionSource`1 completion, Int32 timeout, Task& task, Boolean asyncWrite)
at System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method)
at System.Data.SqlClient.SqlCommand.ExecuteScalar()
at PetaPoco.Database.ExecuteScalar[T](String sql, Object[] args)
at DotNetNuke.Data.PetaPoco.PetaPocoHelper.ExecuteScalar[T](String connectionString, CommandType type, String sql, Object[] args)
at DotNetNuke.Data.DataProvider.AddTabToEnd(TabInfo tab, Int32 createdByUserID)
at DotNetNuke.Entities.Tabs.TabController.AddTabInternal(TabInfo tab, Int32 afterTabId, Int32 beforeTabId, Boolean includeAllTabsModules)
at DotNetNuke.Entities.Tabs.TabController.AddTab(TabInfo tab, Boolean includeAllTabsModules)
at DotNetNuke.Modules.Admin.Tabs.ManageTabs.SaveTabData(String strAction)
at DotNetNuke.Modules.Admin.Tabs.ManageTabs.cmdUpdate_Click(Object Sender, EventArgs e)