data assist should not be installed after security assist.
security assist should be the last extension installed.
install the extensions in any order:
CSS Button Styler
Bing Search Toolkit
eCart
Image Resizer
Validation Tooltips Spry
Dynamic Dropdowns
Dynamic Connections
Dynamic Webcharts
Surveyor
Theme-It
Web Standard Advisor
then install these extensions last in this order:
Data Assist
Form Toolkit
CSS Formbuilder 2.0.1
HTML Editor 3
Design Extender
Security Assist