When you create a file hyperlink in PowerPoint, you may find that the forward slashes in the file path get converted to backslashes, preventing the hyperlink from working in your Presenter '09 published output.
This is a known PowerPoint issue. Use either of the following options to avoid this behavior:
Place the file on a web server or LMS, and use the HTTP URL to create the hyperlink in PowerPoint.
Save your presentation in the backwards-compatible format PowerPoint 97-2003 Presentation.