Had the same issue
I had the same issue, "wa_randompassword.php" apparently not been created, but I looked into my inetpub folder to find that SecurityAssist had created another webassist folder (different from the one created in the site's root folder), with a security_assist folder inside it and happily "wa_randompassword.php" had been created there. So, I moved the file to the correct location.
By the way, I'm working on Windows 7, Dreamweaver CS4 and DataBridge 1.05
Hope it can help.