Problem in insert (UniqueIdentifier) in Table

Question

Greeting

I created my own database and used this method by Ankush Agnihotri (Create And Install ASP.NET Membership Database)to create users asnd membership and roles in my web application projects. see link below which method I used:

 https://www.c-sharpcorner.com/blogs/create-install-asp-net-membership-database

 

I designed form to admin site to create an emplyee account in three steps :

 

First step :create employee account by (Registeration tool) to create user account which will store emplyee account in Users Table.

Second Step: redirect admin  to next page to complet an emplyee form  information. 

Untile this moment a last two steps working correctly.

Third step: an confirmiation appears to admin to catch a ROLE ID and USER ID which represented as (UniqueIdentifier) value to store its in USERSINROLE table as figures below:

 

 

A last two steps (one and tow) working correctly, but a confimation catch this problem:

 

 

So How to solve this problem thanks