RaiseError: File does not begin with '%PDF

I have an application which has below script:

var oDoc = event.target.openDataObject("testing123");

This script works fine if I run it on my local machine.

But I am planning to place the pdf (application) on the server. After placing the pdf on the server, I tried to open the pdf through local browser, I got an error 'File does not begin with '%PDF'.

I added one line:

var thePath = oDoc.path;

After running, I got local machine path where pdf is placed. On Server, no path is coming in the debugger.

Server doesn't have Acrobat install on it. Each user has acrobat to open the pdf

Please advise.