The customer is trying to run PMImport (Patch Management Import). Every time that he runs the PMImport task, it fails right away. Looking at the task and its failure message, it said:
Failure reason: Another instance of Import Patch Data for Windows task is running. Only one instance of a running Import Patch Data for Windows task is allowed. You can stop the running task, schedule current task for a different time or create a job with both tasks included to run them one after another.
In this particular case, the customer had some issues with running out of disk space, which caused some issues with loading pages and running services. Since the SMP server was in a state of partially running tasks, the previous PMImport started tasks didn't properly finish or stopped.
Restart "Altiris Client Task Data Loader" service (this should also call to restart "Altiris Object Host Service" service)
After that, run again the PMImport task.