I get this exception in XACT from August DXSDK.
This looks like .NET related error. I've found it's raported by other .NET users.

I can repeat it:
I play two cues in repeat mode and watch variables in Variables Settings window. I change one of the variables by slider and sort rows by "Scope". One of the variables is monitored.

- Begin Dump Exception -
Exception Type:
System.Data.VersionNotFoundException

Source:
System.Data

Message:
There is no Original data to access.

Clickable StackTrace:
(Unknown Source Location): System.Data.DataRow.GetOriginalRecordNo()
(Unknown Source Location): System.Data.DataRow.GetRecordFromVersion(DataRowVersion version)
(Unknown Source Location): System.Data.DataRowView.GetColumnValue(DataColumn column)
(Unknown Source Location): System.Data.DataColumnPropertyDescriptor.GetValue(Object component)
(Unknown Source Location): System.Windows.Forms.DataGridColumnStyle.GetColumnValueAtRow(CurrencyManager source, Int32 rowNum)
(Unknown Source Location): XACTGui.XACTDataGridTextBoxColumn.Paint(Graphics g, Rectangle bounds, CurrencyManager source, Int32 rowNum, Brush backBrush, Brush foreBrush, Boolean alignToRight)
(Unknown Source Location): System.Windows.Forms.DataGridRelationshipRow.PaintCellContents(Graphics g, Rectangle cellBounds, DataGridColumnStyle column, Brush backBr, Brush foreBrush, Boolean alignToRight)
(Unknown Source Location): System.Windows.Forms.DataGridRow.PaintData(Graphics g, Rectangle bounds, Int32 firstVisibleColumn, Int32 columnCount, Boolean alignToRight)
(Unknown Source Location): System.Windows.Forms.DataGridRelationshipRow.Paint(Graphics g, Rectangle bounds, Rectangle trueRowBounds, Int32 firstVisibleColumn, Int32 numVisibleColumns, Boolean alignToRight)
(Unknown Source Location): System.Windows.Forms.DataGrid.PaintRows(Graphics g, Rectangle& boundingRect)
(Unknown Source Location): System.Windows.Forms.DataGrid.PaintGrid(Graphics g, Rectangle gridBounds)
(Unknown Source Location): System.Windows.Forms.DataGrid.OnPaint(PaintEventArgs pe)
(Unknown Source Location): System.Windows.Forms.Control.PaintWithErrorHandling(PaintEventArgs e, Int16 layer, Boolean disposeEventArgs)
(Unknown Source Location): System.Windows.Forms.Control.WmPaint(Message& m)
(Unknown Source Location): System.Windows.Forms.Control.WndProc(Message& m)
(Unknown Source Location): System.Windows.Forms.ControlNativeWindow.OnMessage(Message& m)
(Unknown Source Location): System.Windows.Forms.ControlNativeWindow.WndProc(Message& m)
(Unknown Source Location): System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
- End Dump Exception -