Sql 2000 Maintenance Plan doesn't retain wizard settings

[Case32]

Using the maintenance plan wizard, I select a non-default location in which to store the backup, and set the remove files older than box to '1' but the next drop-down where you should normally see days/weeks etc is blank. On the completion screen I am seeing that files will be deleted after '1 week' is displayed.
When I then view the properties for this plan I see that neither the backup path nor the remove files older than settings are shown - all fields are blank.

Any assistance gratefully appreciated.

Jason