cuDNN not availabe

I’m trying to install cuDNN 3v and 4v library on my workstation but I have some error.

There is CUDA 7.5 and Theano 0.7. My graphic card is a GTX980ti and the OS is Ubuntu 15.05.

I setted all configuration as mentioned in both cuDNN and theano instruction, but when I try to view the dnn version I have always the same error:
“We can’t determine the cudnn version as it is not available”

For cuda 7.5 it support Ubuntu14.04/15.04 . Does Samples/deviceQuery can detect the GTX980ti correctly? Were the PATH and LD_LIBRARY_PATH environment variables set for cuda/cudnn?