I'm having the same issue on a Windows XP box.
I've tried adding the file to the following directories with no improvement.
C:\Documents and Settings\<Username>\Application Data\Adobe\Dreamweaver 9
C:\Documents and Settings\<Username>\Application Data\Adobe\Dreamweaver 9\Configuration
C:\Documents and Settings\<Username>\Application Data\Adobe\Dreamweaver 9\Configuration\Shared\WebAssist
C:\Documents and Settings\<Username>\Application Data\Adobe\Dreamweaver 9\Configuration\Shared\WebAssist\Library
C:\Documents and Settings\<Username>\Application Data\Adobe\Dreamweaver 9\Configuration\Shared\WebAssist\FormBuilder
C:\Documents and Settings\<Username>\Application Data\Adobe\Dreamweaver 9\Configuration\Shared\WebAssist\FormBuilder\Library
C:\Documents and Settings\<Username>\Application Data\Adobe\Dreamweaver 9\Configuration\Shared\WebAssist\FormValidations
C:\Documents and Settings\<Username>\Application Data\Adobe\Dreamweaver 9\Configuration\Shared\WebAssist\FormValidations\Library
C:\Documents and Settings\<Username>\Application Data\Adobe\Dreamweaver 9\Configuration\Shared\WebAssist\FormValidations\Scripts