terminate called after throwing an instance of ‘std::invalid_argument’ what(): stoi

stoi function crashes program with the error message

"****@****:~> g++ -std=c++0x m1.cpp stimulation.h stims.h Task.h exoskeleton.h ARAIG_Sensors.h Profile.h

ARAIG_Sensors.h:1:9: warning: #pragma once in main file [enabled by default]

Profile.h:1:9: warning: #pragma once in main file [enabled by default]

*****@****:~> a.out StimulationConfig.csv TaskConfiguration.csv SampleProfileConfig.csv SampleOutput.txt

First : a.out
Second : StimulationConfig.csv
terminate called after throwing an instance of 'std::invalid_argument'
  what():  stoi
Aborted

and I can’t figure out why, there is a instance being passed into the function but still returning an error. Can someone please help me out with a solution maybe?

#pragma once
#include <string>
#include <vector>
#include "Task.h"
#include <ostream>
#include "ARAIG_Sensors.h"
namespace m1
{
    class Profile
    {
        ARAIG_Sensors araig;
        std::vector<Task> ToRun;
        std::vector<Task> Completed;
        std::string studentFN;
        std::string studentLN;
        std::string studentSN;
        std::string flightFN;
        std::string flightLN;
        std::string flightEN;
        std::ostream& os;

        struct calibration {
            int Max;
            int Min;
        };

        calibration cal;

    public:
        Profile(std::string fn, std::ostream& o, ARAIG_Sensors& a) : os(o)
        {
            araig = a;

            //parsing student
            std::ifstream infile(fn);
            std::string line;
            std::getline(infile, line);
            int f = line.find_first_of(",");
            studentFN = line.substr(0, f);
            line = line.substr(f + 1);
            f = line.find_first_of(",");
            studentLN = line.substr(0, f);
            studentSN = line.substr(f + 1);

            //parsing flight
            std::getline(infile, line);
            f = line.find_first_of(",");
            flightFN = line.substr(0, f);
            line = line.substr(f + 1);
            f = line.find_first_of(",");
            flightLN = line.substr(0, f);
            flightEN = line.substr(f + 1);

            //parsing calibration
            std::getline(infile, line);
            f = line.find_first_of(",");
            cal.Min = stoi(line.substr(0, f));
            std::cout << cal.Min << std::endl;
            line = line.substr(f + 1);
            cal.Max = stoi(line);



            std::list<Task> temp = araig.gettasks();
            while (std::getline(infile, line))
            {
                for (std::list<Task>::iterator i = temp.begin(); i != temp.end(); i++)
                {
                    if ((*i).getName() == line)
                    {
                        ToRun.push_back(*i);
                        break;
                    }



                }

            }

        }
        void displayToRun()
        {
            for (std::vector<Task>::iterator i = ToRun.begin(); i != ToRun.end(); i++)
            {
                (*i).execute(os);
            }
        }
        void displayCompleted()
        {
            for (std::vector<Task>::iterator i = Completed.begin(); i != Completed.end(); i++)
            {
                (*i).execute(os);
            }
        }
        void displayNext()
        {
            std::vector<Task>::iterator i = ToRun.begin();