While trying to run PMImport it will fail to download AeXPatchDeployment.exe. Error in the logs indicates a file corruption: An error occured while verifying trust for object 'D:\Program Files\Altiris\Patch Management\Downloads\Tools\AeXPatchDeployment.exe.TMP' (UnknownSubjectForm).
Downloaded file has an incorrect or missing digital signature, previous version of the file will not be replaced. An error occured while verifying trust for object 'D:\Program Files\Altiris\Patch Management\Downloads\Tools\AeXPatchDeployment.exe.TMP' (UnknownSubjectForm).
On this scenario IPS detection on the firewall was blocking the download.
Patch Management 8.x
Create a firewall rule or turn of IPS to allow server to download files.