you are using the wrong session variable for the captcha validation
the code to create the captcha image is on your page is:
<img id="capt1" src="../webassist/captcha/wavt_captchasecurityimages.php?width=200&height=50&field=Security_Code_1&bgcolor=0099FF&transparent=false&bgimage=&gridfreq=25&gridcolor=0066FF&gridorder=behind&noisefreq=50&noisecolor=F5F5F5&noiseorder=behind&characters=5&charheight=&font=fonts/MODERNA_.TTF&textcolor=0000CC" alt="security code" width="200" height="50" />
one of the variables that is passed to the wavt_captchasecurityimages.php page is named "field", the value of this variable is used for creating the captcha session variables name:
field=Security_Code_1
the naming convention of the captcha session variable is:
captcha_<value of field url variable>
so the session variable that is crated on your page is:
captcha_Security_Code_1
in the validation, you are using the captcha_Security_Code session variable, edit the validation to use the captcha_Security_Code_1 session instead.