C++ Linked List, bad_alloc

My teacher gave us the main.cpp (mostly just data to test the program) and a header file for a Linked List. I'm pretty sure I have most of it okay, but having issues turning into a vector with the method/parameters he gave us:

vector<string> LinkedList::toVector(bool sorted) const
{
    vector<string> result;

    Node *current = mFront->mNext;
    while (current != mRear)
    {
        result.push_back(string(current->mData));
        current = current->mNext;
    }

    if (sorted)
    {
        sort(result.begin(), result.end());
    }
    return result;
}

I keep getting an error saying that there is bad memory allocation on the push_back line. Any advice?

Edit: I didn't put enough of the code in

The Node class was created in the private access modifier of linkedList.h - code for that is:

private:

    class Node
    {
        friend class LinkedList;

    public:
        inline Node *getNext() const
        {
            return mNext;
        };

        inline string getData()
        {
            return mData;
        }

    private:
        inline Node(string data)
        {
            mPrevious = mNext = 0;
            mData = data;
        }

        string mData;
        Node *mPrevious;
        Node *mNext;
    };

I attempted debugging and that was actually how I found out exactly what line the exception was being thrown from. I'm not sure how to test whether it is push_back that is the issue or whether the string is throwing, as someone suggested.

current->mData should be giving back a string as long as I'm looking at it right, that's what the main.cpp is using to populate everything.