I worked with Binary Poet offline and figured out that he has the 64-bit version of MSVCR100.DLL in the same folder containning the file he is trying to scan. InstallShield detects that MSVCR100.DLL as a dependency and therefore adds the 'Visual C++ 10.0 CRT (x64)' merge module to his installation. In order to get it work-around, remove the file or change the Path environment variable to list a directory containing the 32-bit version of MSVCR100.DLL first.
I would recommend that you use the Dependency Walker to find out the location of dependencies detected on your machine. You can view the full path of the dependencies by selecting the View | Full Paths menu option.
Also, I've submitted the work order IOA-000065378 so that InstallShield will detect the dependencies based on the target CPU architecture wisely in a future release.
Hope that helps.
Hidenori Yamanishi - Senior Software Engineer - Flexera Software: InstallShield Team