Error instantiating new presentation with existing file

Using .NET version 3.0.0.41081. Why would I get an "Object reference not set to an instance of an object" from the following lines of code (File.Exists(filePath) evaluates to true):

Presentation pres = null;

string filePath = @"\\App2\Presentation Slides\02 Services Offering\Consolidated Report Mini Pages.ppt";

if(File.Exists(filePath))

{

pres = new Presentation(filePath); //

}

stack trace: at Aspose.Slides.Presentation.( )
at Aspose.Slides.Presentation..ctor(String file)
at WebPresentationBuilder.SlideDisplay.PresentSlide(String id) in D:\Visual Studio 2008\Projects\WebPresentationBuilder\SlideDisplay.aspx.cs:line 45

Hello,

There could be one more problem with custom properties but now everything already fixed. Please try latest version attached in this post.

Stack trace is too short. Are you sure the file is not locked by another process?

The new build did it! awesome. Thanks.

To my knowledge there was no other process with that file locked up. But it does live in a SharePoint doc library.