Error while creating a new user using server and client side scripting using a web form

[Vinay1]

I created a web form now i want to create a new user when the web form is submitted

here is the client side script for taking the user data from the web form and
sending it to the server side

here is the server side script for taking the user data from the client side and
creating a new user object

user entered data is sent to server side succesfully but i am getting this error