"Error saving document"

Hi,

I have a small problem.I generated a pdf file with some temperory name and later i am renaming the file.When i am trying to rename the file using FileSystem.Rename, i get an exception "Error saving document". I don't understand why am i getting this error.I checked if my file is already open, but it was not.

Please do let me know if you have any ideas.

Thnx in advance.