[c#] Could not load file or assembly 'xxx' or one of its dependencies. An attempt was made to load a program with an incorrect format

I had this error when trying to use the dreadful Business Objects 4 for .Net SDK.

They ship five BusinessObjects*.dll files, but all of them are 64-bit.

To get my webpage to load, I needed to click on Tools\Options, then change this setting in VS2013:

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