VB program Frozen..

[programmingpat]

Hey everyone,
I am making a program that requires the user to enter values and select the correct radio button.
It freezes when I click Ok button and I am not sure why, I think I am not using the Do Until...Loop properly.
Ok Button code:

Public Sub btnOk_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnOk.Click

        Call mainfunction()

    End Sub

I also attached a jpeg of the program to give you guys and idea of it.