There are chances you have to invoke legacy 32 bit COM from 64 bit application. The most common exception I’ve got is the error code 800a0035.
Basically the error code 800a0035 is about the 64 bit process (your application )could not retrieve 32 bit COM information from 64 bit registry. Scott Hanselman had a blog post detailing this issue.
So to make your 32 bit COM works on 64 bit server, when compiling your applicaiton, change active solution platform from [Any CPU] to [X86] to make this application a 32 bit application.