问如何防止此异常:值不属于预期范围。用WaitHandle.WaitAny方法？

EN

public void QueueCompareProcessThread(QueueProcesses Qp)
{
    try
    {
        WaitHandle[] pHandles = Qp.GetRunningProcessesHandles();
        WaitHandle.WaitAny(pHandles);
        Qp.RemoveExitedProcess();   // clearing the process list 
        // strange behavior is while clearing the process list i'm getting the exception in the thread Waitany method
        // Does Waitany method still working after it returns?
    }
    catch (Exception e)
    {
        utils.Log("QProc Exception at QueueCompareProcessThread() Message:" + e.Message + " Trace:" + e.StackTrace);
    }
}