I was stuck in an application where I had to use the 32 bit source for both 32 and 64 bit machines. The application seemed to work fine, except the context menu option in x64 machines.
I found a great post by David Vielmetter on his blog http://davidvielmetter.com/tricks/context-menu-issues-with-gvim-in-windows-7-x64/ and I was able to solve the issue. I think context menu many times create an issue in 64 bit machines and this is a good way to solve them (This is entirely my point of view). If someone has some better suggestions, they are most welcome to comment here. I too would like to learn more on how to create 64 bit context menu options.