SOLUTION!!
I've been having the same problem and noticed that the files worked on computers with FCP7 installed, but I got the error on machines without. The solution is here on this blog, and works perfectly and without FCP7 installed. Just follow the instructions and the codecs needed are there and you just copy them to the Library->Quicktime on the boot drive and you'll be set.
http://www.jonathangrubbs.com/journal/pro-quicktime-codecs-no-fcp/