I'm using Microsoft's 64-bit compiler in 2010. In version 1.1.3 of IACA there were a IACA_VC64_START macro. This didn't work on any of my test projects.
Now in the latest version (2.0.1) the documentation still mentions the IACA_VC64_START macro, however this is now missing from the iacaMarks.h file.
Are you indeed supporting 64-bit output from the Microsoft 2010 compiler, or only Intel's own 64-bit compiler?