Calling Excel Macro's from VB .exe

Hi, I have a simple .exe that opens an Excel sheet, runs a macro and closes:

<code>
Sub Main()

'Opens Excel, runs a macro and closes

Dim xlApp As Excel.Application
Set xlApp = CreateObject("Excel.Application")
xlApp.Application.DisplayAlerts = False
Dim wb As Excel.Workbook
Set wb = xlApp.Workbooks.Open("C:\book.xls")

'wb = Excel.Workbook.Open("C:\book.xls")

' Make it invisible:
xlApp.Visible = False

' Run the macro:
xlApp.Run ("formatWattle")

xlApp.Quit
Set xlApp = Nothing
Set wb = Nothing

End Sub
</code>

When I run the macro from within Excel, it executes in about 2 seconds, start to finish. When I call the macro from an .executable, it takes a few minutes, and sometimes just plain crashes on me.

The .exe is compiled with VB5, since I tried with VB.net and it was just as slow.

If anyone can tell me how to get better results with what I am doing, please fill me in, as it is difficult to find information on something like this.

Many thanks,

.tehwa

just to add another issue, it will execute quickly if the attribute 'xlApp.Visible' is set to 'true', but takes about 30secnds longer if this is set to 'false'.