I'm having the same problem as this. I downloaded the files from the link you said, but I can't find a way to install them. I've tried terminal, synaptic and using different browsers, but nothing is working for me.
I had to reinstall my laptop and now I am unable to install Master Password. I have just upgraded to Java 8 and I get the error message:
The file '/home/magpie/Desktop/masterpassword-gui.jar' is not marked as executable. If this was downloaded or copied from an untrusted source, it may be dangerous to run. For more details, read about the executable bit.
This error is not generated by Master Password and I do not know or understand the system that is generating it; therefore it is hard for me to render assistance with it. I recommend you look into obtaining support from the Ubuntu community.