Printing PDF through 32 Bit PC stopped working

Question

We have 2 different applications one using the WIN32API call and the other one using .Net Process to print the PDF document without opening.  This functionality was working until 3 -5 weeks back in production.  Now we are unable to print with the existing functionality.  Yesterday we come across the same code is working fine when we make a request from 64 bit pc's.  This is strange and I'm not sure whether this is a problem with Adobe or Microsoft.  FYI, 4 days back the all of the sudden it started printing just for a day and it stopped again the next day onwards.
Here's the code we have been using from 2 different applications,
ll_rc = ShellExecuteW ( handle( this ), "PRINT", is_doc_path + ls_full_file_name, ls_Null, ls_Null, 1)
and here is the function definition for the above:
                FUNCTION long ShellExecuteW  (long as_hwnd, string as_lpOperation, string as_lpFile, string as_lpParameters,  string as_lpDirectory, integer ai_nShowCmd ) LIBRARY "shell32"
In .NET, we are using PDFSharp to print.  
Process printJob = new Process();
       printJob.StartInfo.CreateNoWindow = true;
     printJob.StartInfo.Verb = "print";
     printJob.StartInfo.WindowStyle = ProcessWindowStyle.Hidden;
     printJob.StartInfo.FileName = concatenatedFileName;
     printJob.StartInfo.Arguments = '\\' + prntDialog.PrinterSettings.PrinterName.ToString() + '\\';
     printJob.Start();
     printJob.WaitForExit(5000);

Answer 1

Moved to Acrobat SDK