Probably means that you need to read the manual to find out! My guess is that it is in a protection mode because 4ohm speakers were hooked up to an 8ohm amp.
protect mode. Your receiver is probably overheating or you have wires that are crossed. Check the speaker wires first. Some sony receivers are fan cooled and if they failed that means the heat is causing your receiver into protect mode and more than likely a board is fried. But it won't hurt to have it checked. Here is the excuse you need to get a new receiver! cheers