C++ Compiler Error: P1LinkedList.cpp:145: error: call of overloaded ‘to_string(int&)’ is ambiguous

I'm implementing a linked list. I'm getting the error:

P1LinkedList.cpp:145: error: call of overloaded ‘to_string(int&)’ is ambiguous
/usr/lib/gcc/x86_64-redhat-linux/4.4.7/../../../../include/c++/4.4.7/bits/basic_string.h:2604: note: candidates are: std::string std::to_string(long long int)
/usr/lib/gcc/x86_64-redhat-linux/4.4.7/../../../../include/c++/4.4.7/bits/basic_string.h:2610: note:                 std::string std::to_string(long long unsigned int)
/usr/lib/gcc/x86_64-redhat-linux/4.4.7/../../../../include/c++/4.4.7/bits/basic_string.h:2616: note:                 std::string std::to_string(long double)

(I'm compiling my code with g++ -std=c++0x

The method throwing this exception:

std::string P1LinkedList::print(){

    std::string print = "";
    iterator itr = begin();

    for(int i = 0; i < theSize; i++){
        print += std::to_string(itr.current->data) + " ";
        itr++;
    }

    return print; 
}

current is the current Node being pointed to by the iterator. data is an int that is within the Node class.

Node.h:

#ifndef Node_h
#define Node_h

struct Node{

        int data; 
        Node* next; 
        Node* prev; 

        Node(const int & d = 0, Node *p = 0, Node *n = 0); 
};

#endif

Part of my const_iterator.h file where current is declared (my iterator class extends from the '''const_iterator''' class:

    protected:  
        Node *current; 
        int& retrieve() const; 
        const_iterator(Node*p); 
        friend class P1LinkedList; 
};

I'm trying to pass data through to_string as a regular int value, which I thought itr.current->data was doing, but could I possibly be getting this error because it's not passing the int value of data, but a pointer to it instead?