Could not load file or assembly 'Interop.SAPbobsCOM' or one of its dependencies. An attempt was made to load a program with an incorrect format

Hi all experts,

I want to create add on web application for my customer. and in that web application, i want to create web service to create web method to insert and update information in SAP. i created web service by using vs 2010 with .net framework 3.5. after i created, i public into my local iis7 and start to run web service. When i browse web service, it displays me an error like this: "Could not load file or assembly 'Interop.SAPbobsCOM' or one of its dependencies. An attempt was made to load a program with an incorrect format" . I don't know how to solve it.

So does anybody know how i can solve this problem?

Note: it runs in Win 7 64 bit.

Thanks

TONY