I checked the event log and found this warning for ASP.Net 2.0

Event Type:    Warning
Event Source:    ASP.NET 2.0.50727.0
Event Category:    Web Event
Event ID:    1309
Date:        7/21/2008
Time:        1:32:28 PM
User:        N/A
Computer:    APD-WEBSERVER
Description:
Event code: 3005
Event message: An unhandled exception has occurred.
Event time: 7/21/2008 1:32:28 PM
Event time (UTC): 7/21/2008 5:32:28 PM
Event ID: baef31f3ba8f4bccb887ea0a4746bc45
Event sequence: 9
Event occurrence: 1
Event detail code: 0
 
Application information:
    Application domain: /LM/W3SVC/62391181/Root-1-128611351273050299
    Trust level: Full
    Application Virtual Path: /
    Application Path: D:\DotNetNuke_2\Website\
    Machine name: APD-WEBSERVER
 
Process information:
    Process ID: 3936
    Process name: w3wp.exe
    Account name: NT AUTHORITY\NETWORK SERVICE
 
Exception information:
    Exception type: SqlException
    Exception message: Could not find stored procedure 'dbo.GetHostSettings'.
 
Request information:
    Request URL: 
    Request path: 
    User host address: 
    User: 
    Is authenticated: False
    Authentication Type: 
    Thread account name: NT AUTHORITY\NETWORK SERVICE
 
Thread information:
    Thread ID: 7
    Thread account name: NT AUTHORITY\NETWORK SERVICE
    Is impersonating: False
    Stack trace:    at System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection)
   at System.Data.SqlClient.SqlInternalConnection.OnError(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.ExecuteReader(CommandBehavior behavior, String method)
   at System.Data.SqlClient.SqlCommand.ExecuteReader(CommandBehavior behavior)
   at Microsoft.ApplicationBlocks.Data.SqlHelper.ExecuteReader(SqlConnection connection, SqlTransaction transaction, CommandType commandType, String commandText, SqlParameter[] commandParameters, SqlConnectionOwnership connectionOwnership)
   at Microsoft.ApplicationBlocks.Data.SqlHelper.ExecuteReader(String connectionString, CommandType commandType, String commandText, SqlParameter[] commandParameters)
   at Microsoft.ApplicationBlocks.Data.SqlHelper.ExecuteReader(String connectionString, CommandType commandType, String commandText)
   at Microsoft.ApplicationBlocks.Data.SqlHelper.ExecuteReader(String connectionString, String spName, Object[] parameterValues)
   at DotNetNuke.Data.SqlDataProvider.GetHostSettings()
   at DotNetNuke.Entities.Host.HostSettings.GetHostSettings()
   at DotNetNuke.Services.Scheduling.SchedulingProvider.get_SchedulerMode()
   at DotNetNuke.Services.Scheduling.DNNScheduling.Scheduler.CoreScheduler.Halt(String SourceOfHalt)
   at DotNetNuke.Services.Scheduling.DNNScheduling.DNNScheduler.Halt(String SourceOfHalt)
   at DotNetNuke.Common.Initialize.StopScheduler()
   at DotNetNuke.Common.Global.Application_End(Object sender, EventArgs e)
 
 
Custom event details:

For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp.

I tried the MS link but there was no help found..