Is the outlet always hot, or only hot when you're using the toaster oven? Is the circuit GFI-protected? There's too much resistance somewhere, you need to find out where before something bad happens. An EXTREMELY high number of house fires start from faulty electrical systems.
If it were me, I'd make sure the circuit is GFI-protected and that the appliance isn't overrated for the outlet. Some easy tests you could do would be to use the toaster oven on a different outlet, and different appliances on the "trouble" outlet, see what happens.
Do you mean the toaster oven cord, or the actual wire inside the wall that feeds the outlet?