That statement (without the $) works ok in the tester, but it will not run in the live php environment. That requires the $FID_num. The code that WA writes just won't work (at least in my setup).
Your friends over here at WebAssist! These Dreamweaver extensions will assist you in building unlimited, custom websites.
These out-of-the-box solutions provide you proven, tested applications that can be up and running now. Build a store, a gallery, or a web-based email solution.