Just one tiny detail...I don't think it's a very good idea to have the word error in the titlebar...since it's not really an error. Otherwise it should cover the cases when a license need to be agreed to.
"Accept Agreement" [You have sold your soul] "Skip package" [this will skip it's dependencies as well, somewhat difficult to implement?] "Cancel Upgrade" [short-circuit the upgrade/installation] "Help"
PS: Please enable OpenID comments :-/ Or is the spam attacking your blog comments via OpenID as well?