i havent played vendetta in a while and i was going to start playing again, but when i open the updater it says "can't open Contents/info.plist! aborting update failed" so what does that mean and how do i fix it?

What version of what operating system are you using?

the ".plist" says "OS X 10.p.q", but I have no idea what p or q are.

How long is a while?

Alpha/Beta clients WILL NOT update, if you last played before Nov 2004 re-download the instaler from the website, or just give that a try anyway.