cuHook sample failed (Didn't receive the allocation callback)

I have a laptop with 860M, Bumblebee+CUDA7.0.
After a long struggle :
https://devtalk.nvidia.com/default/topic/935811/cuda-setup-and-installation/-bumblebee-cuda7-0-working-but-problems-compiling-examples-2-of-2-/

I managed to compile the included examples.
Unfortunately cuHook in 7_CUDALibraries compiles ok but fails at runtime:

> optirun ./cuHook 
Error: Condition (allocation_cb == 1) failed at cuHook.cpp:115
cuHook sample failed (Didn't receive the allocation callback)

Any clues ? Anything missing that I can install using the methods in the post above ?

Thank you very much in advance.

You’re not running that sample correctly.

Note this comment in cuHook.cpp:

“** The library has to be loaded via LD_PRELOAD, e.g. LD_PRELOAD=<full_path>/libcuhook.so.1 ./cuHook”

That worked, thanks!