You have a recurring event in a Microsoft Windows SharePoint Services 3.0 calendar list. When you use the GetListItems method of the Lists.asmx Web service to obtain all the occurrences of the recurring event, only one item is returned.
Note This problem does not occur when you run a query to obtain all the occurrences by using the SharePoint object model.
To resolve this problem, apply the following hotfix:
975022 Description of the Windows SharePoint Services 3.0 hotfix package (Sts-x-none.msp): September 30, 2009
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.