"System.InvalidOperationException was unhandled" Any Idea?

Below is the very simple code I made that I just cannot get to compile... I only have 3 controls, a button, and 2 text boxes... could anyone please help me make sense of this?  Much thanks!



*** Code ***

Public Class Form1

Dim h As Integer

Dim l As Integer

Dim c As Integer = 0

Dim q As Integer

'Dim n(c) As Integer

Dim nn As String

Private Sub start_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles start.Click

l = low.Text

h = high.Text

While l <= h

q = 3

If (l Mod 2 = 0) Then

GoTo endloop

Else

Continue While

End If

While q < l

If (l Mod q = 0) Then

'n(c) = x

nn = nn + ", " + l

'c += c

MsgBox(l)

Exit While

Else

q = q + 2

End If

End While

endloop:

l += l

End While

End Sub

End Class

*** Error Output ***

System.InvalidOperationException was unhandled
  Message="An error occurred creating the form. See Exception.InnerException for details.  The error is: Object reference not set to an instance of an object."
  Source="Primes"
  StackTrace:
       at Primes.My.MyProject.MyForms.Create__Instance__[T](T Instance) in 17d14f5c-a337-4978-8281-53493378c1071.vb:line 190
       at Primes.My.MyProject.MyForms.get_Form1()
       at Primes.My.MyApplication.OnCreateMainForm() in C:\Documents and Settings\Owner.localhost\My Documents\Visual Studio 2005\Projects\Primes\Primes\My Project\Application.Designer.vb:line 35
       at Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase.OnRun()
       at Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase.DoApplicationModel()
       at Microsoft.VisualBasic.ApplicationServices.WindowsFormsApplicationBase.Run(String[] commandLine)
       at Primes.My.MyApplication.Main(String[] Args) in 17d14f5c-a337-4978-8281-53493378c1071.vb:line 81
       at System.AppDomain.nExecuteAssembly(Assembly assembly, String[] args)
       at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
       at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
       at System.Threading.ThreadHelper.ThreadStart_Context(Object state)
       at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       at System.Threading.ThreadHelper.ThreadStart()