A critical trick that finally worked for me was to understand that the 64-bit ODBC driver and 64-bit ArchiCAD, had to be installed in the 64-bit MS Office environment with the 64-bit database (in my case, MS SQL2 2008). You probably know this by now.
The other critical trick -- essential under early versions of Win7 and versions of Vista -- was/is to run the ODBC manager directly from the directory in which odbcadnn.exe resides, NOT from the START menu or Programs Menu. I think the 64-bit ODBC driver is in ...\system32, not ...\sysWOW64. It's superficially counter-intuitive. (MS confirmed that the START menu and Programs menu shortcut listings triggered the 32-bit ODBC, not the 64-bit one.)
Back when, it was not entirely simple to install "pure" 64-bit MS Office. Aside from various warnings that some things may break under 64-bit Office, or require 32-bit Office, there were also Office-related apps that had no 64-bit version (I don't recall which, now; perhaps Project or Visio or OneNote?). I also recall that I was required to use some (downloadable) MS tools to ensure complete uninstallation of 32-bit Office because the usual remnants left in the Registry triggered subsequent 32-bit installations.
There are many articles on TechNet and its Forums detailing the trials and tribulations of getting 64-bit Office properly operational, along with the ODBC stuff. It probably is easier now than two years ago when I went through this mess.
If you're downloading MS Office (Excel in particular) you may find that the bit-width of the browser you use may trigger the bit-width of what you get (like some versions of Java). For Office 2013, I think the download is both 32 & 64-bit, but be constantly aware of what you're installing. I recommend Revo Uninstaller, to track every file installed, so if you need to uninstall and re-try Office, then you can do it cleanly.
Maybe someone else has more current info.
