opencv(2.4.6.1) compiled with cuda (5.5): can't compile cpu based codes

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Hi, I'm on ubuntu 13.04, have successfully compiled opencv 2.4.6.1 with the latest cuda 5.5. At least I thought it was a success. Because when I try to compile the examples in /opencv-2.4.6.1/samples/c, all I get is:

/usr/bin/ld: warning: libnppc.so.5.5, needed by /usr/local/cuda/lib64/libnppi.so.5.5, not found (try using -rpath or -rpath-link)

And all the consequences of the above:

/usr/local/cuda/lib64/libnppi.so.5.5: undefined reference to `nppGetMaxThreadsPerSM'
/usr/local/cuda/lib64/libnppi.so.5.5: undefined reference to `nppGetStream'
/usr/local/cuda/lib64/libnppi.so.5.5: undefined reference to `Stream'
/usr/local/cuda/lib64/libnppi.so.5.5: undefined reference to `nppGetGpuComputeCapability'
/usr/local/cuda/lib64/libnppi.so.5.5: undefined reference to `Event'
/usr/local/lib/libopencv_gpu.so: undefined reference to `nppSetStream'
/usr/local/cuda/lib64/libnppi.so.5.5: undefined reference to `nppGetGpuNumSMs'
/usr/local/cuda/lib64/libnppi.so.5.5: undefined reference to `nppGetPointerMemoryType'
collect2: error: ld returned 1 exit status

This being my first use of cuda and compilation with opencv, I don't know where to go from this. The only libnppc.so.5.5 I have found was for linux suse. Is there any thing I didn't set up properly when installing cuda (did with the .deb packages from nvidia site)? Cuda examples compile properly, opencv compiled and installed without any error.

Edit: I've just tried to compile an example (houghlines.cpp) in the gpu section of the samples (opencv-2.4.6.1/samples/), with:

g++ houghlines.cpp -o houghlines `pkg-config --cflags --libs opencv` -lopencv_gpu

and it compiled and I could run the program all right. The above problem with libnppc remains with cpu examples (such as those in samples/c and samples/cpp) and any other older program I wrote...