Hacked AC_RunActiveContent.js

I am looking for a new secure method to run Flash content on client websites.
In the past 8 months I have had 9 client sites hacked by using the AC_RunActiveContent.js. Some of my clients sites redirect to some unsafe domain and most recently my clients site gives the message “This page requires AC_RunActiveContent.js” A unsecure browser will allow this js file to download and install a program called “security tool” that takes over your computer and wants a credit card number to fix your problems…I am looking for a secure method to run flash content without the AC_RunActiveContent.js or a way to secure the AC_RunActiveContent.js from hackers. Anything you have in this direction is welcome. I cannot be the only designer that has expereinced this. Help please