WordPress stats API on own server

Hi,

I am running wordpress on my own apache within a home domain. I wanted to add wordpress stats plugin and I got asked for API. I also have an account on wordpress.com, so I used the api that I got with that registration, but my blog (on my server) says that “current API is assigned to user XXX”… and its alwas red on the top. Plus I dont see the stats page on my dashboard as I should….
do I still need api even when I run wordpress on my own server? Why cant I use the one I have?
thank you!