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That last - the 8Omin - means '8 Ohms minimum'.
It should show up when you are part way through a Factory Reset of the receiver... so it is part way through the steps to a reset, I think. If you don't mind losing all settings, go through the rest of the reset too:
Straight then Power starts the reset, when it is in Standby.
Then you get SP IMP 8OHM MIN on the screen.
Then you press RIGHT PROGRAM ARROW until INIT-CANCEL shows up.
Press STRAIGHT until INIT-ALL comes up.
Press STANDBY to turn it Off.
And when the POWER button is next pressed, factory settings will be applied.