Jscript Run time error while executing the scripts in C#

Hi ,

While executing scripts in Windows7_64 bit if i run the following code it is thing runtime error at the first line.The code is written in C#.

var oex = Sys["OleObject"]("Excel.Application");
  oex.visible = false;
  var owb=oex.workbooks.open(FoundFullPath);
  var ows=owb.worksheets("Sheet1");