I got this error when I was working with Dev Express Reporting Tool. I investigated why I am getting this run time error.
Then I came to know that actually corresponding dll is missing. I checked on Application Reference list and GAC list for the dll for which meta data is not found.
I surprisingly notice targeted dll was both place. Then why I am missing the dll? To solve the problem, I simply set copy to local to true.
I got the problem fixed. Aha great release! I am very glad to share my experience in my blog.