>>>>>Did you test your PDF2PS function standalone?
>>>>
>>>>
>>>>Yes, If I am not using Parallel Fox the same is running Fine. It seems to me that when there is One CPU involved, the DLL is not shared and may be when there are more than One CPU there may be Sharing Problem of DLL , so error might be generated. Is it so ?
>>
>>If you're sure that this code works fine if not running parallel, one of the possibilities is to wrap the code to call this function in try/catch block and retry in case of the failure the second time.
>
>Ok, Can you please Give the Specific code for that purpose in my this case. I tried Try Catch Last Time as suggested by Tore Sir, but could not comprehend it completely.
>It would be an Example for me to learn Try Catch even.

This is how I would write this (pseudo-code):

local llReTry
llReTry = .f.
try
   call to the function that may cause error
   
catch to loError
   if loError.ErrorNo = 2027
       llReTry = .t.
   else
      log the error
   endif
endtry

if m.llReTry
   try
       one more time calling the same code
   
   catch to loError
       * if error, just log the second time
   endtry
endif