Again, apologies for this major inconvenience this has caused you.
Please keep in mind that the upload of the PMImport is live, and the uploaded data was unforseeably corrupted, and that is where the problem originated. Therefore, there is no true resolution to any data already lost in an environment that has already downloaded the corrupt data.
Moving forward; disabling the setting to 'Delete previously downloaded...,' unless one is using that to clean up the environment when exclusions need to be implemented for updates no longer needed, is the best preventive measure.
The full database restore is a great way to recover the lost data, hence it was added to the KM article. Unfortunately, in your environment, you will need to review with the other Altiris Admins and see what the best time saver for your group would be, for this advice was merely to assist with data loss recovery and is a solid resolution if able to be performed, but it goes without saying that it will impact on the enviornment.
Additionally, the policies and package resource associations are stored in the database, and the restore would bring them back into the Console. The manual download of the Patch Packages may be in order if a package clean up process removed those, but they should be in tact on default: C:\Program Files\Altiris\Patch Management\Packages\Updates. Nothing more would need to be performed.
Please let me know if there are any remaining concerns and I will be happy to help.
Sincerely,
Joshua