My totem needs decoder. ????
 

I got a good basic install and some packages install easily but some do not.
I can't play cd's/DVD's. Totem says it needs a decoder. What do I do?

Is it CD's or DVD's specifically? Are they commercial movies, for example?
I can't exactly help with music CD's other than suggest you search for 'codecs' but for commercial movies, you likely need 'libdvdcss' which is a DVD movie de-cryption library required to play most DVD's.
Using Google, you can very easily locate a libdvdcss package to download and install. It's quick and simple, and should solve the DVD issue if this is infact the problem.
Let me know how you make out, or if you need further help :)

Totem actually does not. The backend (or engine) that totem "uses" (or: for which Totem is a front-end) requires probably some kind(s) of decoder(s)/plugin(s). It's usually Xine or GStreamer, it depends on the distribution. And I know there are already several threads about this matter here at LQ, along with solutions, tips and howtos, so I suggest you use the Search found at the top of the page to locate those threads. I guess it's one of the most common questions how you enable mp3/dvd/wma/wmv/etc. playback on Fedora with your favourite player Totem/VLC/Mplayer/Xine/other.