Open a terminal window, navigate to the folder where your executable is located and do the following
sudo chmod -x PRO.x86_64
./ PRO.x86_64
The 1st line makes sure that the file will be recognized as an executable file.
I'm not sure if the 2nd line requires sudo or not I'm currently on my home pc that has windows on it.
After it should run just fine.
Hope it helped (although servers are down atm so you won't be able to log in but you can still try to run it).