When I turn the system on I get the following message:
"Short in speaker wire, system is disabled and will turn off in 15 seconds. Reboot the system."

The system used to work fine but I get this message even when nothing (i.e., no speakers, TV, MP3, etc.) is plugged into it.

No troubleshooting info regarding this error message in the manual.

Any suggestions on how to repair?

Unit is less than a year old.