How do I rescue a Final Cut 7 project that elicits "File Error: Wrong Type" when I try to open it in FCP?
After installing SetFile (instructions below), go to terminal and execute this command:
setfile -c &quot;KeyG&quot; -t &quot;FCPF&quot; INSERT_FILENAME_HERE

According to SetFile's man page, &quot;-c&quot; sets the creator and &quot;-t&quot; sets the type.
I found what the type and creator should be set to in Peppy's second post on this thread: http://hintsforums.macworld.com/archive/index.php/t-16983.html
SetFile can be installed as part of the Xcode Command Line Tools by opening Terminal and typing:
xcode-select --install

But if I recall that sometimes fails so you might also try downloading it from the Apple Developer site.