System.NullReferenceException: Object reference not set to an instance of an object.
   at NVelocity.Runtime.RuntimeInstance.GetTemplate(String name, String encoding)
   at NVelocity.Runtime.RuntimeInstance.GetTemplate(String name)
   at NVelocity.App.VelocityEngine.GetTemplate(String name)
   at ZSHTML.Nvlt.vltContextToHtml(String tempFile, VelocityContext vltContext) in F:\www\ZhaoShangHtml\ZSHTML\Nvlt.cs:line 71