Summary: Impress crashes on displaying a slide show after opening a power point 
file on disk that is currently opened Microsoft Power Point 2007.

OOo-dev 3.3.0 
DEV300m77 (Build:9496)

Windows 7 32-bit

Steps to reproduce: 
1: Open Microsoft Power Point 2007
2: Create a new blank presentation
3: Save blank presentation to disk as a 2003 .ppt file
4: Start Impress leaving PowerPoint open: Start->Programs->Ooo-dev3.3->Impress
5: In the Impress wizard select Open Existing Project
6: Click the Open Button and a new window should show up
7: Navigate to the saved file and open it
8: A new box should pop up saying that the file is already open: click Open Copy
9: Click Slide Show menu and start the slide show
10: A new window should pop up displaying that Open Office has crashed and 
telling you that your document will be recovered

I have been able to successfully reproduce this many times with existing files.  
Upon further testing it is possible to reproduce this without having to create a 
new PowerPoint document every time.  

I also tested if this is a more generic error rather than some specific 
interaction with PowerPoint, and it appears that the only constraint is that the 
document is opened as not being able to be shared with other applications.  
These steps will also cause Impress to crash:

1: Start->Programs->OOo-dev3.3->Impress
2: Click open button
3: Open an existing PowerPoint presentation
4: Leaving the first impress running, open a new instance of impress: Start-
>Programs->OOo-dev3.3->Impress
5: Click the open button
6: Open the same document you opened in the first impress session
7: You will now see the message saying the document is already open.  Click the 
Open Copy button
8: Click on the slide show menu and then the Slide Show option to start the 
slide show
9: You should now see a message indicating that OpenOffice has crashed and will 
attempt to recover your document when it restarts.

I also tested this bug with a .odp instead of a .ppt file using the steps listed 
above and it does not crash.