What error are you getting - compiler/runtime? I can see that scanf might be an issue as you don't include <cstdio> (I'm unclear if <conio.h> does that for you). Also, you are mixing input mechanisms (cin and scanf) - it is best to pick one and be consistent.
Also, you posted a code snippet. You should not post questions like these as code snippets but as new questions.
For Each ctrl As Control In Me.Controls("pnlMainPanel").Controls
If ctrl.GetType Is GetType(System.Windows.Forms.Panel) Then
For Each subCtrl As Control In ctrl.Controls
If subCtrl.GetType Is GetType(System.Windows.Forms.TextBox) Then
If subCtrl.GetType Is ...