The heat of fusion of gold was forgotten.
A constant heat capacity is seriously inaccurate here: the temperature varies too much for that. Such a computation demands to integrate the variable heat capacity over the temperature range, or easier, to find a table of the enthalpy contents as a function of the temperature. Available for elements like gold, and called "steam table" for water.
In the inaccurate computation, the temperature difference and the heat capacities happen to compensate. This is because gold atoms are heavy, so there are fewer to store energy than in water. Also, water molecules attract an other, but this bond gets more and more broken by heat in the liquid, which increases the heat capacity. A different element like carbon would not give the same result as water and gold.
Just as a side note, degrees Celsius are written °C (° and big C), and the proper unit for temperature differences is the Kelvin, written big K. Don't forget neither to write all units, it helps to avoid mistakes. While chemists like grams, the SI unit is the kg; as well, you may often find calories in older texts, instead of joule.