Error while loading PDF Preset file

Dear All,

I am trying to create a PDF of the InDesign Document after my process. For that I load the preset file generate the PDF and unload Preset file from the server. On this it gets removed properly from the temporary folder also.
Problem is when I run the process second time using the same preset file InDesign Server throws an error "This file is already open by another user or another application. This file may be stored on a network server and cannot be opened until the other user closes it."

It works only if I restart the server. Can somebody help me on this its urgent.

Thanks in advance.

Regards
Farzana.