The Stand Alone Extensions are not compatible with DW CC.
While DW CS 6 was still available, the stand alone extensions where replaced with Data Bridge.
Data Bridge is a consolidation of the Data Driven extensions we offer, and also includes an upgraded version of Data Assist.
to Use Data Assist and Security Assist in DW CC, you will need to upgrade to Data Bridge. Otherwise, continue using them in the previous version of Dreamweaver.