? about Ubuntu Live CD

I'm using a live cd of Ubuntu 7.10 Desktop and when I go to some sites w/ Firefox it asks me to install plugins (flashplayer or gnash swf). It won't let me install them, it says they are invalid. Is this because it's a live cd and not a permanent installation on my hard drive? I'm trying this out on my laptop and luckily it sees my Cisco pcmcia wireless card, but if I recall it doesn't see the wireless card in my desktop, so I am debating about ditching XP totally on my desktop since I'd like to use wireless (I may go buy a brand name pci card though and hope Ubuntu sees it).