Visual C++ x64 woes

Hello all!

So I was pointed to this place after asking in the WinApi forum. I use Visual Studio 2008. I made a windows form program that works perfectly under the 32bit compiler. But when I changed the platform to x64, these things stopped working (they don't do anything):

MessageBox
CreateWindow
DialogBox

And when I call GetLastError, I get 193 (0xC1) which, according to MSDN, is:

ERROR_BAD_EXE_FORMAT
193 (0xC1)

%1 is not a valid Win32 application.

I have Windows 7 professional 64 bit edition and an x64 architecture for my CPU.

My suspicion is that I only have the 32 bit header files for WinApi.

Can anyone enlighten me?

Thanks in advance!

Did you compiled the application for x64? Or did you just copy it? One of the main reasons for this error is that there is a mismatch between the application and supporting dll's.....for example, a 64-bit process trying to load a 32-bit dll and vice-versa....

Yeah that sounds right. When the solution was created it was set to use the Win32 platform, and following some instructions on MSDN, I just used the configuration manager to change the platform to x64. How would I create/modify a project so that it uses 64 bit dlls? I didn't really see about 32/64 bit when creating a project (I usually create empty projects).

Update:

So according to wiki, System32 contains the 64bit versions of the dlls on a 64bit windows. And my compiler does indeed load dlls from that folder. And all my header files are loaded from the right place. So why the error?

Update:

I found out what was wrong: I had a manifest file to use windows xp visual styles. I copied and pasted stuff from MSDN. It was geared towards 32bit apps.