I have attempted to set up an expiration policy to delete items, and it
does not appear to be functioning. What am I missing?

The policy is set up on a custom content type. The content type inherits
from the Task content type. I've added the site column called Date
Completed to the content type. I've also defined an Information
Management Policy configured as follows:

* Enable Expiration is checked

* The retention period is a time period based on the item's
properties: Date Completed + 60 Days

* When the item expires, perform this action: Delete

The content type is added to a list that I have in the same site
collection. It is the only content type attached to that list. The list
contains three items with a Date Completed of 10/6/07, 10/7/07, and
10/10/07.

In Central Admin, I see the following timer jobs, each of which ran at
the end of the day yesterday:

* Expiration Policy

* Information Management Policy

I even tried Central Admin >> Operations >> Information Management
Policy Configuration >> Expiration >> Process Expired Items Now.

None of this seems to be getting rid of the expired items.

Any suggestions?