I have to use the keyboard to navigate through the installer, and even after installation I still cannot use my mouse to interact with the GUI.
We tried on OSX 10.9.5 too and we did not reproduce such issue. Do you have any specific settings on your environment? Have you already installed JAVA product on your MAC?
Is it possible to get the NeoLoad logs files accessible through the menu "Help-->Open logs folder..."?
If you can't get them through the UI they are stored under $HOME/.neotys/neoload/v5.1./logs