This is a restriction of WordPress when it's run in a network format, because of the inherent vulnerabilities / hack-ability of Javascript, iFrames, etc. If you try to add scripted code to a page or post, it will not save correctly.
Only Network Administrators can add these for you, which we are happy to do. Open a support ticket and attach the code in a separate text file or Word doc; give us the URL of the page/post the code should be added to; and we'll get it added for you, no charge.