I have opened a program from a website, has my MBP been infected with a virus?
About the website you visited should give you some idea what you downloaded.

Here is Feb. 2015 Whois Record showing the site was banned (closed) by the Authorities.

So what ever you downloaded, get rid of it, it can not be trusted.

http://venturebeat.com/2015/02/09/kickasstorrents-goes-down-after-its-domain-is-seized-but-makes-a-quick-return/

http://kickasstorrents.eu/news/kickasstorrents-is-not-shut-down-kat-ph-domain-seized/



As long you only downloaded the dmg and not installed it your should be fine by just deleting that dmg package.