C++ :: Error Initializing Map - Ambiguous Operator

Okay so inside my ArcherArmor.cpp, I'm trying to figure out why the map initializer list isn't working, but for some reason I keep getting "Error C2593: 'operator =' is ambiguous". Here is my code:

I also have a class which ArcherArmor is derived from, that has a struct called `Armor`, which I left out for simplicity. The main problem is that error! The only thing I can think of is that im initializing the map wrong.

//ArcherArmor.h
#include <string>
#include <map>
class ArcherArmor {
private:
map <int, Armor> soldier_armor;
public:
void ArcherArmor_shop();

[Code] .....