when you save a preset, the preset is associated with the initially selected design type, so if you select 3 Column Fixed as the design type, then edit the Design, the preset you save will only be available the next time you open CSS Sculptor if you select 3 Column Fixed as the design again.
What version of Dreamweaver are you using?
The type of crash you describe sounds like it is caused by a memory leak in Dreamweaver, this can be caused by a number of different factors, such as other extensions you have installed, number of Dreamweaver Windows that are open such as the Files panel and the Server behaviors panel.
Whenever you experience unexpected behavior in Dreamweaver, the first thing to do is to Delete the Dreamweaver Cache file from the users configuration folder:
common_installation_issues.pdf
