The first two lines in sub WorkBook_Open a
ActiveWindow.WindowState = xlNormal
Application.Top = 0

Most of the time, this works fine. Occasionally the 2nd line fails with:
Run-time error '1004':
Method 'Top' of object' _Application' failed

I am running Excel 2003

What could be causing this and how can I fix it?

MANY thanks for any help.