Tensorflow with CUDA: ImportError

I've installed TensorFlow step by step like described in this tutorial from NVIDIA (Ubuntu 16.04 Desktop, GTX 970):

http://www.nvidia.com/object/gpu-accelerated-applications-tensorflow-installation.html

Every steps completes without errors, but if I try to import TensorFlow in Python afterwards I'm always gettin' this error message:

>>> import tensorflow as tf Traceback (most recent call last): File "<stdin>", line 1, in <module> File "/usr/local/lib/python2.7/dist-packages/tensorflow/__init__.py", line 24, in <module> from tensorflow.python import * File "/usr/local/lib/python2.7/dist-packages/tensorflow/python/__init__.py", line 72, in <module> raise ImportError(msg) ImportError: Traceback (most recent call last): File "/usr/local/lib/python2.7/dist-packages/tensorflow/python/__init__.py", line 61, in <module> from tensorflow.python import pywrap_tensorflow File "/usr/local/lib/python2.7/dist-packages/tensorflow/python/pywrap_tensorflow.py", line 28, in <module> _pywrap_tensorflow = swig_import_helper() File "/usr/local/lib/python2.7/dist-packages/tensorflow/python/pywrap_tensorflow.py", line 24, in swig_import_helper _mod = imp.load_module('_pywrap_tensorflow', fp, pathname, description) ImportError: libcudart.so.8.0: cannot open shared object file: No such file or directory Failed to load the native TensorFlow runtime. See https://github.com/tensorflow/tensorflow/blob/master/tensorflow/g3doc/get_started/os_setup.md#import_error for some common reasons and solutions. Include the entire stack trace above this error message when asking for help. 

I've installed the CUDA-Toolkit to /opt/cuda/toolkit (also cuDNN). I already tried to symlink:

sudo ln -s /opt/cuda-toolkit /usr/local/cuda sudo ln -s /opt/cuda-toolkit /usr/local/cuda-8.0 

Or this:

sudo export LD_LIBRARY_PATH="$LD_LIBRARY_PATH:/opt/cuda-toolkit/lib64:/opt/cuda-toolkit/extras/CUPTI/lib64 sudo export CUDA_HOME=/opt/cuda-toolkit 

But the error remains. Can anybody give me a hint why this error occurs? Thanks a lot :)