Free tools server validation dialogue box after inserting a captcha isn't stable and disappear immediatly having clicking the function in the menubar

I have downloaded the "free tools" on mine account and installed it on mine dreamweaver CS6. All the icons buttoms were appearing. So I try to install the captcha tool in an existing PHP form, After the captcha was placed in the form, dreamweaver was asking me to add server validation. When I click on the menu forms/validation/server validation, I was expecting a dialogue box to be open for choosing additional parameters. After clicking in the menu the box was only appearing a flash time and disappear immediately without having the time to put some info in it. I try to reinstall this functionality by redownloading it and reinstalling with "adobe extention mgr" but it is still doing the same reaction. Could you tell me why this is happening and how I could stabilize this functionality?