Hi Alexander,
Please provide more information:
About package - If I understand you correcly it's imported by using ASDK via VBS script, after it was imported can it be opened via UI?
You did not ansevered on question about multicasting? How it's configured?
Also please verify does this package exists on package server which manage this client machine? (if you use Package Servers and they manage different subnets or clients manually assigned to some package servers).
Did you try to import same package via UI and create new MD policy, what will be happen in this case? is this package comming on client?
Regards,
Dmitri