Facebook games will not work on xubuntu 11.10 how do I fix?

I just had xubuntu 11.10 put on my computer and know nothing about the system. Adobe flash player is installed and up to date, I have only had this running for a few days. My YouTube works just fine but when I try to play a game on Facebook it tells me that my flash player needs to be upgraded. Being used to Windows, I went into my Firefox plugin menu, and there is not even an adobe flash plugin listed. (I thought maybe it wasn't active) I was wondering if/how this can be fixed? Can someone can explain it to me, even though I know absolutely nothing about the operating system?