I'm re-installing a 7.1 Site Server.

When I select in the console to make it a Package and Task server, it sends the jobs to the Server but when you double click the task the package URL are pointing at itself so cant download or run.

How do I change the location of packages so it downloads from another server?

Does this help

How do I move Patch Management updates to a new location, or remove update downloads?

Configuring Package Location on your Package Server

Check this discussion also

http://www.symantec.com/connect/forums/moving-download-location-altiris-patch-management-71-notification-server#comment-7424901

https://www-secure.symantec.com/connect/forums/can-i-redirect-package-delivery-path

Sorry that's not the problem. 

I dont need to change where the packages download TO. I need to change where they download FROM.

I've rebuilt a site server so it's blank with nothing on it any more.

But the database still thinks it's a site server that can distribute packages, so it's trying to download packages from itself that are not there any more. I need to change it so the download URL point to another server.

Did you remove the Package services from the console itself?  The last time I did this I uninstalled Task and Package and let the whole thing sit for a day.

I think that there's a daily package task that runs.  I can check into this more later.