Do You have any clues?
Your test was with 1 email address. This error is occurring when there is a database of about 100 records.
Could it be a bad record? Is there limits on number of emails?
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.