That header file looks okay. There may be an include you need, but I don't see anything that should need one. The error must be in another file in your solution/project.
Is this file #included after another file that could perhaps have an error in it? This is generally the type of error that you get when you forget a ';' in a file that is #included earlier in the code.
You'll want to consider adding #include <iostream> to the top of the header at a minimum, you may need/want another as well. Also, as AD said, you'll want to resolve the std namespace somehow, either directly or with a using statement.
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 ...