Won't update

I don't know if this a Portable problem or a Firefox one. The update to 3.0.2 went fine, but with this one clicking "Restart Firefox now" closes the browser, then pretty soon the updater shows up in Task Manager, but instead of seeing "Firefox is installing..." I get the Windows "Run as.." dialog box. When I click that, it and the updater are gone and I start over (4 times). Any ideas?