the disallowed parent paths error means that the ../ notation cannot be used to reference file a directory down.
instead use include virtual and site relative paths:
<!--#include virtual="/WA_ValidationToolkit/WAVT_Scripts_VB.asp" -->
<!--#include virtual="/WA_ValidationToolkit/WAVT_ValidatedForm_VB.asp" -->
in your DW Site definition, there is a setting for "Create Links Relative to", if you set this option to Site, DW will use the include virtual code and site relative links for you.