Changing to a other sheet in Excel

[vbquest]

Dear vb users,

When I have started Excel in VB5, I want to change to an other sheet.

Code:
Dim XLsheet As Object

Set XLsheet = GetObject("c:\book.xls")
XLsheet.Application.Visible = True

Worksheets("test").Activate

In the last sentence occurred an error:

Method 'Worksheet' of object '_global' failed

What do I wrong?
Knows someone a other source?

Mary