I've been struggling for a week now with an exception i'm getting during registration. I'm not totally sure if this is related to the users online module but i keep getting the following errors in my eventlog at the same date time of my registration. What is purgeusersonline exactly doing? i guess it's updating or deleting from the usersonline table by calling the sp. i checked both sp DeleteUsersOnline and UpdateOnlineUser and there doesn't seem to be anything wrong with them. So which query could be giving more than 1 value???

first log entry: 

<LogProperties><LogProperty><PropertyName>THREAD ID</PropertyName><PropertyValue>93</PropertyValue></LogProperty><LogProperty><PropertyName>TYPE</PropertyName><PropertyValue>DotNetNuke.Entities.Users.PurgeUsersOnline</PropertyValue></LogProperty><LogProperty><PropertyName>EXCEPTION</PropertyName><PropertyValue>Subquery returned more than 1 value. This is not permitted when the subquery follows =, !=, &lt;, &lt;= , &gt;, &gt;= or when the subquery is used as an expression.The statement has been terminated.</PropertyValue></LogProperty><LogProperty><PropertyName>RESCHEDULED FOR</PropertyName><PropertyValue>10/10/2012 11:41:17 AM</PropertyValue></LogProperty><LogProperty><PropertyName>SOURCE</PropertyName><PropertyValue>STARTED_FROM_BEGIN_REQUEST</PropertyValue></LogProperty><LogProperty><PropertyName>ACTIVE THREADS</PropertyName><PropertyValue>1</PropertyValue></LogProperty><LogProperty><PropertyName>FREE THREADS</PropertyName><PropertyValue>0</PropertyValue></LogProperty><LogProperty><PropertyName>READER TIMEOUTS</PropertyName><PropertyValue>0</PropertyValue></LogProperty><LogProperty><PropertyName>WRITER TIMEOUTS</PropertyName><PropertyValue>0</PropertyValue></LogProperty><LogProperty><PropertyName>IN PROGRESS</PropertyName><PropertyValue>1</PropertyValue></LogProperty><LogProperty><PropertyName>IN QUEUE</PropertyName><PropertyValue>5</PropertyValue></LogProperty></LogProperties>

 second entry:

<LogProperties><LogProperty><PropertyName>AssemblyVersion</PropertyName><PropertyValue>6.2.3</PropertyValue></LogProperty><LogProperty><PropertyName>PortalID</PropertyName><PropertyValue>-1</PropertyValue></LogProperty><LogProperty><PropertyName>PortalName</PropertyName><PropertyValue /></LogProperty><LogProperty><PropertyName>UserID</PropertyName><PropertyValue>-1</PropertyValue></LogProperty><LogProperty><PropertyName>UserName</PropertyName><PropertyValue /></LogProperty><LogProperty><PropertyName>ActiveTabID</PropertyName><PropertyValue>-1</PropertyValue></LogProperty><LogProperty><PropertyName>ActiveTabName</PropertyName><PropertyValue /></LogProperty><LogProperty><PropertyName>RawURL</PropertyName><PropertyValue /></LogProperty><LogProperty><PropertyName>AbsoluteURL</PropertyName><PropertyValue /></LogProperty><LogProperty><PropertyName>AbsoluteURLReferrer</PropertyName><PropertyValue /></LogProperty><LogProperty><PropertyName>UserAgent</PropertyName><PropertyValue /></LogProperty><LogProperty><PropertyName>DefaultDataProvider</PropertyName><PropertyValue>DotNetNuke.Data.SqlDataProvider, DotNetNuke.SqlDataProvider</PropertyValue></LogProperty><LogProperty><PropertyName>ExceptionGUID</PropertyName><PropertyValue>359ab0c8-5939-4602-ab49-9cea99655b4e</PropertyValue></LogProperty><LogProperty><PropertyName>InnerException</PropertyName><PropertyValue>Subquery returned more than 1 value. This is not permitted when the subquery follows =, !=, &lt;, &lt;= , &gt;, &gt;= or when the subquery is used as an expression.

The statement has been terminated.</PropertyValue></LogProperty><LogProperty><PropertyName>FileName</PropertyName><PropertyValue /></LogProperty><LogProperty><PropertyName>FileLineNumber</PropertyName><PropertyValue>0</PropertyValue></LogProperty><LogProperty><PropertyName>FileColumnNumber</PropertyName><PropertyValue>0</PropertyValue></LogProperty><LogProperty><PropertyName>Method</PropertyName><PropertyValue>System.Data.SqlClient.SqlConnection. </PropertyValue></LogProperty><LogProperty><PropertyName>StackTrace</PropertyName><PropertyValue /></LogProperty><LogProperty><PropertyName>Message</PropertyName><PropertyValue>System.Data.SqlClient.SqlException: Subquery returned more than 1 value. This is not permitted when the subquery follows =, !=, &lt;, &lt;= , &gt;, &gt;= 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.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.InternalExecuteNonQuery(DbAsyncResult result, String methodName, Boolean sendToPipe)

   at System.Data.SqlClient.SqlCommand.ExecuteNonQuery()

   at Microsoft.ApplicationBlocks.Data.SqlHelper.ExecuteNonQuery(SqlConnection connection, CommandType commandType, String commandText, SqlParameter[] commandParameters)

   at Microsoft.ApplicationBlocks.Data.SqlHelper.ExecuteNonQuery(String connectionString, CommandType commandType, String commandText, SqlParameter[] commandParameters)

   at Microsoft.ApplicationBlocks.Data.SqlHelper.ExecuteNonQuery(String connectionString, String spName, Object[] parameterValues)

   at DotNetNuke.Security.Membership.Data.SqlDataProvider.DeleteUsersOnline(Int32 timeWindow)

   at DotNetNuke.Security.Membership.AspNetMembershipProvider.DeleteUsersOnline(Int32 timeWindow)

   at DotNetNuke.Entities.Users.UserOnlineController.UpdateUsersOnline()

   at DotNetNuke.Entities.Users.PurgeUsersOnline.UpdateUsersOnline()

   at DotNetNuke.Entities.Users.PurgeUsersOnline.DoWork()</PropertyValue></LogProperty><LogProperty><PropertyName>Source</PropertyName><PropertyValue /></LogProperty></LogProperties>

Hey Sebastian nice to hear from you again. Thank you for being there always ready to help.

I've actually checked this before and there doesn't seem to be any issue with the sp, although i have previously made the mistake of replacing it by one sp of my own, but i restored the correct version of it i even deleted it completely and recreated it just to be sure:

GO
/****** Object:  StoredProcedure [dbo].[DeleteUsersOnline]    Script Date: 10/11/2012 09:48:00 ******/
SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO


ALTER PROCEDURE [dbo].[DeleteUsersOnline]
    @TimeWindow int    
AS
BEGIN
    DECLARE @dt datetime
    SET @dt = DATEADD(MINUTE, -@TimeWindow, GETDATE())

    DELETE FROM dbo.AnonymousUsers WHERE LastActiveDate < @dt

    DELETE FROM dbo.UsersOnline WHERE LastActiveDate < @dt
END

I don't believe this is the issue at hand here, there's definitely something else i'm missing.  I've check all the sp related to the table usersonline but there doesn't seem to be any issue with them.