Hi nuexzz,
Thanks for the pics, that explains things better. It is the conversion step that you are having problems with after all, rather than with actual compilation of the project.
I don't know why the upgrade is not working for you, there's nothing particularly funky about the project files that would cause it to fail. I'm afraid I don't use Visual Studio 2010 myself to be able to test it out. Maybe someone else on here who does use it can help?
Has it worked for you before? Nothing has changed in the solution and project files for a while so maybe your files have got corrupted somehow. First of all I suggest you try deleting all the source files and checking out the whole source tree again from the SVN repository before re-trying.
Most likely though it is the missing 64-bit build platform on your PC that is preventing the solution from converting (after all, this is what the messages in the log seem to imply). If you're feeling brave you can try editing the solution and project files in notepad and removing all references to the 64-bit build (the files are just plain XML) before loading them again into VS2010. Or you can just install the Windows Software Development Kit as I suggested above. This would be the preferred solution as you won't be able to compile to 64-bits otherwise, just 32-bits.
Good luck! Cheers, Nik.