error while loading shared libraries: libcudart.so.5.5: cannot open shared object file: No such file or directory

It happens when the system can't find the dynamic linker bindings, though you probably set every environment correctly and compiled the program successfully.

Here is the solution.

32-bit: sudo ldconfig /usr/local/cuda/lib

64-bit: sudo ldconfig /usr/local/cuda/lib64

Thanks.(http://stackoverflow.com/questions/10808958/why-cant-libcudart-so-4-be-found-when-compiling-the-cuda-samples-under-ubuntu)