Hi @shankar431 ,
If I recall correctly you will need the older IIS management pack to successfully import the Orchestrator management pack, Orchestrator's "core" has not changed much since many years so it may be one of the reasons why you still need older management packs.
If you're having trouble to find them, you can check over here:
https://systemcenter.wiki/
You can try importing the latest Orchestrator management pack and check what dependencies it requires:
Microsoft System Center 1801+ Management Pack for Orchestrator
----------
(If the reply was helpful please don't forget to upvote and/or accept as answer, thank you)
Best regards,
Leon