When you make an attempt, please open your browser console's Network (or similar) tab and you should see that right before this error, the browser makes a request to a PHP file like wiki_cp.php?panel=install&progress=1
Please send me the content from that tab that the server responds with (usually under a section called "Response"). Normally it looks like gibberish. I believe in this case the installer is trying to ask you a question but for some reason something else is happening.