That has to do with the server side code that filters the result. I couldn't debug that with the datepicker code alone. If you attach the page I might be able to spot it.
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.