Recently upgraded from 5.x.x to 6.2.0. I thought everything was running great, however I was attempting to add a page to an existing website and I received the following error message.

Error: is currently unavailable. DotNetNuke.Services.Exceptions.ModuleLoadException: Subquery returned more than 1 value. This is not permitted when the subquery follows =, !=, <, <= , >, >= or when the subquery is used as an expression. The statement has been terminated. ---> System.Data.SqlClient.SqlException: Subquery returned more than 1 value. This is not permitted when the subquery follows =, !=, <, <= , >, >= or when the subquery is used as an expression. The statement has been terminated. at System.Data.SqlClient.SqlConnection. (SqlException exception, Boolean breakConnection) at System.Data.SqlClient.SqlInternalConnection. (SqlException exception, Boolean breakConnection) at System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj) at System.Data.SqlClient.TdsParser.Run(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj) at System.Data.SqlClient.SqlDataReader.ConsumeMetaData() 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) at System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method, DbAsyncResult result) at System.Data.SqlClient.SqlCommand.RunExecuteReader(CommandBehavior cmdBehavior, RunBehavior runBehavior, Boolean returnStream, String method) at System.Data.SqlClient.SqlCommand.ExecuteScalar() at Microsoft.ApplicationBlocks.Data.SqlHelper.ExecuteScalar(SqlConnection connection, CommandType commandType, String commandText, SqlParameter[] commandParameters) at Microsoft.ApplicationBlocks.Data.SqlHelper.ExecuteScalar(String connectionString, CommandType commandType, String commandText, SqlParameter[] commandParameters) at Microsoft.ApplicationBlocks.Data.SqlHelper.ExecuteScalar(String connectionString, String spName, Object[] parameterValues) at DotNetNuke.Data.SqlDataProvider.ExecuteScalar(String ProcedureName, Object[] commandParameters) at DotNetNuke.Data.SqlDataProvider.ExecuteScalar[T](String ProcedureName, Object[] commandParameters) at DotNetNuke.Data.SqlDataProvider.AddTabAfter(TabInfo tab, Int32 afterTabId, Int32 createdByUserID) at DotNetNuke.Entities.Tabs.TabController.AddTabInternal(TabInfo tab, Int32 afterTabId, Int32 beforeTabId, Boolean includeAllTabsModules) at DotNetNuke.Entities.Tabs.TabController.AddTabAfter(TabInfo tab, Int32 afterTabId) at DotNetNuke.Modules.Admin.Tabs.ManageTabs.SaveTabData(String strAction) at DotNetNuke.Modules.Admin.Tabs.ManageTabs.cmdUpdate_Click(Object Sender, EventArgs e) --- End of inner exception stack trace ---

So I thought that it may be related to this website only so i decided to quickly see if I could add a page to yet another existing website and I received the identical error message.

Does anyone have a suggestion as to where to start looking for a fix to this issue?

Regards