Getting error while creating excel in server ?

Um.

You do realize that to use InterOp to Excel, you need to have Excel installed on the server, don't you?
And if you don't, you get exactly the error you are seeing?
And that almost no webservers have any part of Office installed by default?

Seriously, you don;t want to try and do interop in a production environment, because it s very unlikely that the app you want will be installed - and you can't access any installation on the client for security reasons.

Depending on exactly what you are trying to achieve, you might be better off looking at Excel file writer assemblies - there are quite a few of them out there, and some are quite good.