The Linux binary that you download is for x86/x64 architecture, and won't work on ARM architecture that the RPi uses. You should be able to download the source from github and compile it on the RPi though.
My latest project has been to get a masternode up and running on a Raspberry Pi 256Mb version, and now that has been successful as well.
I moved the swapspace to a USB-stick and increased it's size to be on the safe side, and it seems to work fine.
KiB Mem: 185844 total...
Ok, so I got it up and running. It's showing ,1 in the masternode list, so I guess now I need to wait for it to receive a MN payment to see if it really works.
This was done on a RPi 1 Model B with 512Mb of RAM. As you can see from the "top" command, there is not much free RAM, so it would...
It takes about 15 minutes for darkcoind to start, but after that it seems ok. Unfortunately I need to wait until my old MN IP gets out of the system to test again, think that's why I can't see the RPi IP in the masternode list. Will try again in a couple of hours.