Here is the stack trace:
        Source:HP.QTP.Backend.Entities
        Target:QTP.BackEnd.Core.DocumentIfsLib.IScriptSetting get_ApplicationSettings()
           at HP.QTP.Backend.Entities.TestDocument.get_ApplicationSettings()
           at HP.QTP.Backend.Entities.TestDocumentBase`1.SetValueByNameInGlobalSettings(String key, String attr, Object& newVal, Int32 changeDefault, Int32 setDirtyBit, Int32 changeProp, PERSISTTYPES ptPropType, Int32 bReadOnly)
           at HP.QTP.Backend.Features.RecoveryScenariosFeature.RecoveryScenariosFeature.RestartRun(Object state)
           at System.Windows.Threading.ExceptionWrapper.InternalRealCall(Delegate callback, Object args, Int32 numArgs)
           at MS.Internal.Threading.ExceptionFilterHelper.TryCatchWhen(Object source, Delegate method, Object args, Int32 numArgs, Delegate catchHandler)
        Message:Object reference not set to an instance of an object.
        Additional Information
        SharpDevelop Version : 4.1.3.0-00000000
        .NET Version         : 4.0.30319.34209
        OS Version           : Microsoft Windows NT 6.1.7601 Service Pack 1
        Current culture      : English (United States) (en-US)
        Running under WOW6432, processor architecture: x86-64
        Terminal Server Session
        Working Set Memory   : 183968kb
        GC Heap Memory       : 39457kb
        An unexpected error occurred.
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