I talked about a similar issue here:
http://splunk-base.splunk.com/answers/10946/authorizationfailed-http-403-when-clicking-on-the-link-in-an-alert-email?page=1#27520
The fix is to update local.meta with the new owner of the search.
The search won't run because the former user does not exist, hence the permissions that the non existent user has don't allow the search to run. I can't answer as to why this isn't in the product, but I have a defect filed on the behavior that will be turned into a feature like this in the future. Seems to me that you should be able to change ownership via the UI to specific users, at least with users assigned to the admin role.
... View more