building IlmImf 2.2.0 with Visual Studio 2012 error

Trying to build libopenexr on Windows here and running into a build 
problem I've never had before.

I successfully built ilmbase and ran the "install" target into a 
centralized location, then added that as the ilmbase prefix in the exr 
cmake file.

When I try to build IlmImf, I get this error:

2>------ Build started: Project: IlmImf, Configuration: Debug x64 ------
2>  Building Custom Rule 
D:/paul/src/openexr-2.2.0/openexr-2.2.0/IlmImf/CMakeLists.txt
2>  CMake does not need to re-run because 
D:\paul\src\openexr-2.2.0\openexr-2.2.0\build\IlmImf\CMakeFiles\generate.stamp 
is up-to-date.
2>  Generating b44ExpLogTable.h
2>C:\Program Files 
(x86)\MSBuild\Microsoft.Cpp\v4.0\V110\Microsoft.CppCommon.targets(172,5): error 
MSB6006: "cmd.exe" exited with code -1073741515.

Any ideas?