What is the OS?
I'm on OSX Snow Leopard, but sent the file to a collaborator on Windows and he had the same problem. Although visually, the file appears fine, I'm guessing it might have been corrupted somehow.
The good news is that Macs can give us some data to help diagnose the problem (see http://forums.adobe.com/message/4199358#4199358 for how to collect it), but the bad news is it may not tell us more than it's in the text module, which seems pretty likely and not very definitive.
I'm having exactly the same problem with CS6. Three of my Indesign doscuments crash when amending paragraph styles. Its driving me mad.
I was going to install Indesign on my Mac to see if that crashed too but after reading this post I wont bother.
How can we get this issue looked at by Adobe? I'm happy to provide the 'offernding' documents to the InDesign team.
I really dont want to go through the process of creating brand new documents and new styles just in case it doesnt help.