The Autodesk Update site has a new Hotfix item. The description is a bit vague: This hotfix addresses issues related to deleting or modifying walls, a crash may occur.
You need to make sure that you read the Readme file. You need Web Update #1 installed first too. There is a hotfix for 32 bit and 64 bit versions. Surprisingly low tech patch process. Same hotfix applies to each version so just repeat for the others if you have them too.
It's a good idea to keep an eye on this site every now and then.
[Edit: Aaron Rumple posted at AUGI that this hotfix disables the 2009 UI Revit.ini hack that permits users to use the 2009 user interface instead of the Ribbon. Stay tuned to the thread or here for an update.]