You’re probably running into false positives. Please report these at the appropriate place for your virus scanner. The Tiled installers are built in a controlled environment at AppVeyor, so it is very unlikely that they would actually be infected by a virus.
And until they have removed the false positive, I guess you have to tell your virus scanner to not block Tiled somehow.
Yeah, sorry about that, but it’s against spammers. I think new users are limited to one hyperlink and you were trying to do a post with three links.