Не могу найти ошибку!! В чем дело?

Imports System
Imports Microsoft.VisualBasic
Imports system.Drawing
Imports system.windows.forms
 
 
  class app
      public shared sub main()
          dim frm as new form1
          Application.run(frm)
      end sub
  end class
 
 
Public Class Form1
Inherits Form
Dim Tx As New TextBox
Dim Bt As New Button
Dim S As String
Dim a() As String
Dim b() As integer
Dim i As integer
Dim j As integer
Dim q as integer
 
Public Sub New()
    Clientsize=new size(300,600)
    Me.text="programm_2"
    Me.backcolor=color.lime
    Tx.size=new size(200,400)
    tx.multiline=true
    tx.font=new font("Arial",16)
    Tx.location=new point(5,5)
    Controls.add(tx)
    Bt.Size=new size (100,50)
    Bt.Location=new point(30,410)
    Bt.text="RUN"
    Controls.Add(Bt)
    Addhandler bt.click, addressof bt_click
 
End sub
 
Private Sub Bt_Click (ByVal Sender as system.object, byval e as system.eventargs)
   a=split(tx.text," ")
for i=0 to ubound(a)
    
        if instr("aeuioy",a(i))<>0 then
            b(i)=b(i)+1
        end if
    
next
q=b(0)
for i=1 to ubound(b)
    if b(i)>q then
    q=b(i)
    end if
next
for i=0 to ubound(a)
    tx.text=s+a(i)+" "
    s=tx.text
    if b(i)=q then
    tx.Selectionstart=len(s)-len(a(i))
    tx.SelectionLength=len(a(i))
    tx.select()
    end if
next
End sub
 
End class

Imports System
Imports Microsoft.VisualBasic
Imports system.Drawing
Imports system.windows.forms
 
 
  class app
      public shared sub main()
          dim frm as new form1
          Application.run(frm)
      end sub
  end class
 
 
Public Class Form1
Inherits Form
Dim Tx As New TextBox
Dim Bt As New Button
Dim Bt1 As New Button
Dim S As String
Dim a() As String
Dim bkv As String
Dim b() As integer
Dim i As integer
Dim j As integer
Dim q as integer
Dim n as integer
 
Public Sub New()
    Clientsize=new size(300,600)
    Me.text="programm_2"
    Me.backcolor=color.lime
    Tx.size=new size(200,400)
    tx.multiline=true
    tx.font=new font("Arial",16)
    Tx.location=new point(5,5)
    Controls.add(tx)
    Bt.Size=new size (100,50)
    Bt.Location=new point(30,410)
    Bt.text="RUN"
    Controls.Add(Bt)
    Addhandler bt.click, addressof bt_click
    Bt1.Size=new size (100,50)
    Bt1.Location=new point(160,410)
    Bt1.text="Next"
    Controls.Add(Bt1)
    Addhandler bt1.click, addressof bt1_click
End sub
 
Private Sub Bt_Click (ByVal Sender as system.object, byval e as system.eventargs)
   a=split(tx.text," ")
for i=0 to ubound(a)
    redim preserve b(i)
        for j=1 to len(a(i))
        bkv=mid(a(i), j, 1)
        if instr(1,"aeuioy",bkv)<>0 then
            b(i)=b(i)+1
        end if
        next
    
next
q=b(0)
for i=1 to ubound(b)
    if b(i)>q then
    q=b(i)
    end if
next
for i=0 to ubound(b)
msgbox(cstr(b(i)))
next
for i=0 to ubound(a)
    if b(i)=q and i=0 then
    tx.Selectionstart=0
    tx.SelectionLength=len(a(i))
    tx.select()
    b(i)=0
    end if
    if b(i)=q and i<>0 then
    for j=0 to i-1
    n=n+len(a(j))
    next
    tx.Selectionstart=n+i
    tx.SelectionLength=len(a(i))
    tx.select()
    b(i)=0
    end if
next
End sub
 
Private Sub Bt1_Click (ByVal Sender as system.object, byval e as system.eventargs)
for i=0 to ubound(a)
    if b(i)=q then
    for j=0 to i-1
    n=n+len(a(j))
    next
    tx.Selectionstart=n+i
    tx.SelectionLength=len(a(i))
    tx.select()
    b(i)=0
    end if
next
end sub
End class