To get rid of the old files and allow RealPlayer to do what it needs to, you need to go to its cache and delete the files manually. To find the location, go to the Window menu and choose "Clip Info" (command-I). Follow the path to find and delete all files with the extension "smil," and any that contain "smil" followed by a numeral. The default path that RealPlayer uses to store these files is /private -> tmp -> 501 -> Cleanup At Startup. If you choose to type this manually in Terminal, put "Cleanup At Startup" in quotes to avoid a "too many arguments" message.

