Debugging Problems with native-maven-plugin

Any idea what could cause native-maven-plugin to fail with LNK1112 arch
conflicts on some systems but not others?

In both the good and bad cases I'm using the same envFactory and appear to
have the same native visual studio tools installed.

i'm Running with '-X' not seeing an indication of what is causing the
problem. I believe it relates to tool paths. Please let me know if you have
any suggestions on how to increase verbosity or investigate the problem.

Thanks

Peter

*Errors: *
[INFO] --- native-maven-plugin:1.0-alpha-5:link
[DEBUG] (f) attach = true
[DEBUG] (f) compilerProvider = msvc
[DEBUG] (f) envFactoryName =
org.codehaus.mojo.natives.msvc.MSVC2008x86AMD64EnvFactory
[DEBUG] (f) linkerExecutable = lib
[DEBUG] (f) linkerStartOptions = [/MACHINE:x64 /nologo]

cmd.exe /X /C "lib /MACHINE:x64 /nologo /out:libclib-win64.lib
...myobjfiles..."
fatal error LNK1112: module machine type 'X86' conflicts with target
machine type 'x64'

*Compilation Example: *
cmd.exe /X /C "cl.exe /c /nologo /Dwinamd64_profile /DMYDEFx64
/DNDEBUG /DWINDOWS /EHsc /MD /DAPR_DECLARE_STATIC
/DAPI_DECLARE_STATIC /DAPU_DECLARE_STATIC -Icproj\cpp
-Icproj\win64\cpp -IC:\Java\jdk1.7.0_21\include
-IC:\Java\jdk1.7.0_21\include\win32
-Icproj\win64\lib\target\includes\apr\include
-Icproj\win64\lib\target\includes\apr-util\include
-Icproj\win64\lib\target\includes\apr-iconv\x64\include
/Focproj\objs\myobj.obj
-c cproj\cpp\myclass.cpp"