Couple of Things ...
I upgraded my Inspiron Mini 9 from the original 8.04 to the 9.04 Remix on Saturday. Things went well until I switched into "classic" display mode and rebooted. There's a nasty bug in Remix that causes your files, programs, task bars, and so on to disappear after changing display modes. There are a number of fixes available but I reinstalled 9.04 Remix three times before finding one that actually worked. Ouch!
I also had the experience with installing Flash plug-ins that didn't work. By the third try, I found a bash script, perfectbuntu that automates most of the proprietary multimedia installations that don't come "out of the box". Give this guy a medal! You can find the script here: www.category5.tv/content/view/164/77/