The link in the Downloads section is most definitely working:
RED Modding CenterFalse positives by an anti-virus or browser security settings can flag it as dangerous and block the download, or automatically delete the file/restrict access to it once it's been downloaded. However, the upload is definitely active and available.
I've checked both RED MC and REDitor II, and they're working fine on my PC. With Vlad's site back online, there's no reason they shouldn't, unless your anti-virus/security settings are blocking it.
If it's suddenly disappeared from your PC, chances are your anti-virus got rid of it, possibly after receiving an automatic update. It's just a matter of reinstalling it and adding the appropriate exception in your A/V.