I've been working on this project for some time now, without any problems.
This morning I started PE4 and opened my project. Then I selected Media/Project and dragged the scroll bar to the bottom, where I knew my Titles were that I was working with last night. Then it crashed. I repeated this procedure three times with the same result.
Then I remembered something I did last night. I'd removed a wave file (generated by SmartSound) from the Timeline, from the Media/Project, and from the hard drive (into Recycle Bin). So I restored the file from the Recycle Bin and started PE4 again (didn't add it to the Project). This time it worked fine. Tried it another couple of times and it worked.
Then I deleted the wave file again, and PE4 still starts and works fine, and I was able to finish my Titling.
I think this is too much of a coincidence not to be connected with this file in some way. Is there a 'gotcha' I'm missing? Has anyone encountered anything like this before?