Converting Word to Pdf

Hi,
I am trying to convert a word file to Pdf via windows service in windows server 2012.
In one of my server its running fine, but the same is not working in another 2012 server.
I am using Microsoft.Office.Interop.Word version 12.0.0.0.
Code snippet;
Microsoft.Office.Interop.Word.ApplicationClass wordApplication = new Microsoft.Office.Interop.Word.ApplicationClass(); wordDocument = wordApplication.Documents.Open( ref paramSourceDocPath, ref paramMissing, ref paramMissing, ref paramMissing, ref paramMissing, ref paramMissing, ref paramMissing, ref paramMissing, ref paramMissing, ref paramMissing, ref paramMissing, ref paramMissing, ref paramMissing, ref paramMissing, ref paramMissing, ref paramMissing); ...