go to the download center page here:
downloadcenter.php
in the products list, click the link for CSS Form Builder 2 to go to the CSS form Builder download page.
In the Known Issues section, look for the link titled:
CSS Form Builder 2: Support Fix - A JavaScript error occurs when installing Form Toolkit after CSS Form Builder 2
the webassist folder is in the configuration folder. For help locating the configuration folder, see the common installation issues pdf:
common_installation_issues.pdf
once you locate the configuration folder go to :
configuration/shared/webassist