Locking up when going into "Slide Properties"

Hi Folks,

I've been using Presenter since 2006 in its various iterations, but I ahve never had this issue:

When I go into "Slide Properties" and select my levels and slide advance functions and then go out, it stays locked in a loop and does't save the changes.

Let me give you a few tidbits that might be relevant:

1 - This is by far the largest single project file I have produced.  I have imported the audio narration and the narration is 3.5 hours in length.  I am wondering if the AP file that has been created is just too big and is locking me up.  However, I tried splitting the project into three sections and I am still having the same problem ... so I am doubting file size is an issue.

2 - I mported the audio before I started working with the Slide Properties. (I am wondering if I should import audio last.)

3 - I am using Office 2010

4 - When I force the program to close using Task Manager I get a pop up that tells me the AP Output file cannot be opened. (Whatever that means.)

Has anybody else experienced this? ... and more importantly, what was the fix?

I've wasted 10 hours chasing my tail and I could use some help.