for the first error:
what version of Dreamweaver are you using?
What version of Security Assist?
What other extensions, including version numbers do you have installed?
have you tried Deleting the Dreamweaver Cache file from the users configuration folder:
for the second error:
<?php require_once("Connections/*filename-here*.php"); ?>
Dreamweaver is using the "virtual" syntax because in your Site Definition, the "Create Links Relative To:" option is set to Site. If you change that to "Document" instead, Dreamweaver will use the "require_once" syntax.