after clicking one the 18c for Linux link I get the following error "Error, System error. Please re-try your action. If you continue to get this error, please contact the Administrator."
I have already tried from Chrome and Firefox, in private browsing and removing cookies.
I've just tried downloading the 18c for Linux x64 and it's giving me the option to open/save the file.
Seems to be working for me. I'm using Firefox as a browser.