I had the same problem. It turns out that there is a copy of faad2 that breaks mplayer. I've heard that it came from a freshrpms repository, but I'm sure that mine didn't. How I got this problem on my pc remains a mystery. Anyway... the solution is to download an older copy of faad2, such as this one... http://rpm.livna.org/fedora/6/i386/faad2-2.0-19.20050131.lvn6.i386.rpm and install it over the current with the following command rpm -i --force faad2...rpm I am saying this all from memory, so I might not have the details exactly right, but that is the jist of it. There are a couple threads on www.fedoraforum.org that discuss it. On Fri, 2007-01-19 at 17:09 -0600, Aaron Konstam wrote: > When I run mplayer on an mpg fie: > mplayer file.mpg > > I get the error on my FC6 machine as follows: > mplayer: symbol lookkup error /usr/lib/libavcode.so.51: undefined symbol > ffaacDecOpen > Does anyone understand this error and know what to do about it? > > -- > Aaron Konstam <akonstam@xxxxxxxxxxxxx> > -- Kim Lux, Diesel Research Inc.