Can't seem to delete a managed timesheet period!

[T Lin]

The managed timesheet periods interface in the Admin tab of Project Web
Access 2003 sucks badly. I created a timesheet period 10/17/2005-10/20/2006
and saved. Then I accepted some task updates from PWA users. Then I
noticed that my timesheet period ends in 10/20/2006 not 10/20/2005 like I
wanted. So now I want to delete that timesheet period but the Delete button
is greyed out. How do I get rid of that timesheet period?

thanks,
Tony