Blog stats

I installed the blog stats plug in to wp 2.6 and 2.6.2 blogs. But I am prompted for username and password every time, even though I already logged in to admin control panel, and no matter what I enter, I cannot log in. What account am I supposed to enter please, my blog admin log in details, or wordpress.com account, the one which has api key info?

I ask becaause I really do not want to go through all that change password woffle from wordpress again, clikc on link to verify ect. I have lost no passwords, just that I can never log into stats!

I never had this trouble at my older blogs, using stats plug in.