Hi Davados
Someone else told me about this issue and I'm seeing it too now, so the website appears to be broken at present. Shows this:
I can hopefully fix, I'm guessing @slasher rolled out an update as he is kindly hosting the Arcade Sim website for us. All the actual data for Arcade Sim is hosted here by the folks at Dif. Some great folks in the community, so I've not had to pay for hosting!
Anyhoo, so for now, here is a link to the Installer exe from my dropbox:
https://www.dropbox.com/s/dy9cgg2c71y5k91/Arcade Simulator Setup.exe?dl=0
Download that and run it, and everything should install fine from there. Remember in this 'legacy' version of Arcade Sim you'll need to also install MFME and update it from v20.0 to v20.1 (this won't be a requirement later, although dev of the open source successor Oasis is on hold due to health).
Hopefully that should all work for you, and you'll be back Arcade Simulating again!