The web service converts a Fahrenheit Temperature into Celsius.

Here's the server source code:
Code:
Imports System.Web.Services

<System.Web.Services.WebService(Namespace:="http://localhost/Test1/Service1")> _
Public Class Service1
	Inherits System.Web.Services.WebService

#Region " Web Services Designer Generated Code "

	Public Sub New()
		MyBase.New()

		'This call is required by the Web Services Designer.
		InitializeComponent()

		'Add your own initialization code after the InitializeComponent() call

	End Sub

	'Required by the Web Services Designer
	Private components As System.ComponentModel.IContainer

	'NOTE: The following procedure is required by the Web Services Designer
	'It can be modified using the Web Services Designer.  
	'Do not modify it using the code editor.
	<System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
		components = New System.ComponentModel.Container
	End Sub

	Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
		'CODEGEN: This procedure is required by the Web Services Designer
		'Do not modify it using the code editor.
		If disposing Then
			If Not (components Is Nothing) Then
				components.Dispose()
			End If
		End If
		MyBase.Dispose(disposing)
	End Sub

#End Region

	' WEB SERVICE EXAMPLE
	' The HelloWorld() example service returns the string Hello World.
	' To build, uncomment the following lines then save and build the project.
	' To test this web service, ensure that the .asmx file is the start page
	' and press F5.
	'
	'<WebMethod()> _
	'Public Function HelloWorld() As String
	'   Return "Hello World"
	'End Function

	<WebMethod(Description:="This method converts a temperature in " & _
		   "degrees Fahrenheit to a temperature in degrees Celsius.")> _
	Public Function ConvertTemperature(ByVal dFahrenheit As Double) _
									   As Double
		Return ((dFahrenheit - 32) * 5) / 9
	End Function

End Class
Here's the client source code:
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 TextBox1 As System.Web.UI.WebControls.TextBox
	Protected WithEvents Label1 As System.Web.UI.WebControls.Label
	Protected WithEvents Button1 As System.Web.UI.WebControls.Button

    '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.
        InitializeComponent()
    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 ws As New ConvertSvc.Service1
		Dim dFahrenheit As Double
		Dim dCelsius As Double
		Try
			dFahrenheit = Convert.ToDouble(TextBox1.Text)
			dCelsius = ws.ConvertTemperature(dFahrenheit)
			Label1.Text = dCelsius.ToString()
		Catch
			Label1.Text = "Conversion failed."
		End Try
	End Sub
End Class
When running the application, code execution always skips to the Catch block after the line dCelsius = ws.ConvertTemperature(dFahrenheit).

Any ideas what's going on?