To resolve this issue, first uninstall RealPlayer from Control Panel - for instructions, see:
Next, delete the RealPlayer application folders - see: Delete the RealPlayer application folders (clean uninstall)
Once done, restart your PC and download a fresh copy of RealPlayer by visiting: http://www.real.com/
I hope this helps. If the issue persists, please try these solutions: "Something has gone wrong while running msiexec"