I looked at liquidnet's support FAQ section and they say:
"the 'From' header should be an existing email account inside your Email Manager of your Hosting Control Panel."
Do you have that from address registered?
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.