Electrolytes are substances that conduct electricity when in an aqueous solution. These include the ionic compounds and the strong acids and bases. (ch3ch2)2o is an organic compound. Thus, it is covalent so you would expect this to be a nonelectrolyte or a weak electrolyte.
MgI₂ is an ionic compound between the Mg²⁺ and I⁻ ions. Thus, you would expect this to be an electrolyte.