There was a hotfix for Revit Architecture 2010 (Structure and MEP as well) released on Friday, August 21. The hotfix isn’t very specific, but simple…This hotfix addresses issues related to deleting or modifying walls, a crash may occur.
Definitely make sure you read the Readme file as this hotfix requires you to rename a file, then copy a new one into it’s place. You also have to have the latest build (service pack) installed.
The hotfix can be downloaded HERE.