Perhaps because a) I don't use Vista by XP Pro
The themes in firefox are over and above windows themes, the windows themes control the active window Title bar. The firefox themes don't touch this they control the way firefox elements are displayed, e.g. toolbars, menu, tabs, status bar, etc.
I waited much longer than 1-2 minutes and it didn't even do me the courtesy of displaying a server busy, it simply isn't working.