%1 is not a valid Win32 application - Nsight

Hello,
I am running CUDA 6.5, Nsight 4.1 and the latest Nvidia Drivers (64 bits application).
When I try to debug (Nsight/Start Cuda Debugging), I get the following error
" %1 is not a valid Win32 application (System.ComponentModel.Win32Exception)".
Do not know what to do.
Regards
W.