I created a addpermissions.aspx to set all the permissions to all users.

 you will need to create some form objects to put the low and high portal ids you want check.

Here is code

Public Class WebForm1

Inherits System.Web.UI.Page

#Region " Web Form Designer Generated Code "

'This call is required by the Web Form Designer.

<System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()

End Sub

Protected WithEvents txtportalid As System.Web.UI.WebControls.TextBox

Protected WithEvents Button1 As System.Web.UI.WebControls.Button

Protected WithEvents txtendportalid As System.Web.UI.WebControls.TextBox

Protected WithEvents Label1 As System.Web.UI.WebControls.Label

'NOTE: The following placeholder declaration is required by the Web Form Designer.

'Do not delete or move it.

Private designerPlaceholderDeclaration As System.Object

Private Sub Page_Init(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Init

'CODEGEN: This method call is required by the Web Form Designer

'Do not modify it using the code editor.

End Sub

#End Region

Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load

'Put user code to initialize the page here

End Sub

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

Dim strProviderPath As String = PortalSettings.GetProviderPath()

Dim installMemberRole As Boolean = True

Dim objPortalController As New PortalController

Dim arrPortals As ArrayList

Me.Label1.Text = arrPortals.Count.ToString

Dim objportal As DotNetNuke.Entities.Portals.PortalInfo

Dim intReadFolderPermissionID As Integer

Dim objPermissionController As New DotNetNuke.Security.Permissions.PermissionController

Dim objPermission As New DotNetNuke.Security.Permissions.PermissionInfo

Dim objFolderController As New DotNetNuke.Services.FileSystem.FolderController

Dim objFolderPermissionController As New DotNetNuke.Security.Permissions.FolderPermissionController

Dim PortalCount As Integer

Dim toInte As Integer

Try

toInte = Convert.ToInt32(Me.txtendportalid.Text)

Catch ex As Exception

Exit Sub

End Try

Dim i As Integer

Try

i = Convert.ToInt32(Me.txtportalid.Text)

Catch ex As Exception

Exit Sub

End Try

While i < toInte

If Not objportal Is Nothing Then

Dim folders As ArrayList = DotNetNuke.Common.Utilities.FileSystemUtils.GetFolders(objportal.PortalID)

For Each folder As DotNetNuke.Services.FileSystem.FolderInfo In folders

Dim FolderItem As New ListItem

Dim arr As ArrayList = objPermissionController.GetPermissionByCodeAndKey("SYSTEM_FOLDER", "READ")

For Each objPermission In arr

If objPermission.PermissionKey = "READ" Then

' add READ permissions to the All Users Role

FileSystemUtils.SetFolderPermission(objportal.PortalID, folder.FolderID, objPermission.PermissionID, Integer.Parse(glbRoleAllUsers), "")

Exit For

End If

Next

Next

End If

End While

End Sub

End Class