Compiling cuda samples fail

Hi, I’m using win7 Ultimate x64. My graphics card is a GTX 670. I reinstalled VS2012 Ultimate and upgraded to Update 4. Also reinstalled cuda_5.5.20_winvista_win7_win8_general_64.exe . When I load up CUDA SAMPLES\Samples_vs2012.sln in VS2012 and choose BUILD > Build Solution, I get the following errors. Note that VS2012 is successful at building most samples; however 10 failed.

nvcc : fatal error : Could not set up the environment for Microsoft Visual Studio using ‘C:/Program Files (x86)/Microsoft Visual Studio 11.0/VC/bin/…/…/VC/bin/vcvars32.bat’

The above error occurs when compiling the following samples:
6_Advanced\cdpAdvancedQuicksort
0_Simple\cdpSimplePrint
0_Simple\cdpSimpleQuicksort
6_Advanced\cdpBezierTessellation
6_Advanced\cdpLUDecomposition
6_Advanced\cdpQuadtree
0_Simple\simpleSeparateCompilation

Then I get a whole bunch of the following fatal errors:

13>d:\dev\api\cuda\bin\v5.5\cuda samples\0_simple\matrixmulcublas\matrixmulcublas.cpp(56): fatal error C1083: Cannot open include file: ‘cuda_runtime.h’: No such file or directory
9>d:\dev\api\cuda\bin\v5.5\cuda samples\3_imaging\cudaencode\include\types.h(15): fatal error C1083: Cannot open include file: ‘NVEncodeDataTypes.h’: No such file or directory
9> VideoEncoder.cpp
9>d:\dev\api\cuda\bin\v5.5\cuda samples\3_imaging\cudaencode\include\videoencoder.h(27): fatal error C1083: Cannot open include file: ‘nvcuvid.h’: No such file or directory

I have read the compile instructions at http://docs.nvidia.com/cuda/cuda-samples/. Is there something I have overlooked?

Thanks for any help.