Delete file using remove() in C++

Hi Experts,
I am hoping you can help me... I am trying to delete a file once I am done with it using C++.  I am compiling with Visuall C++ 6.0 into a dll.  I don't have the luxury of using C# since the code that is calling the DLL is not compatible with it.  The last line is where my trouble begins...  Here is my code:

#include <string>
#include <sstream>
#include <fstream>
#include <stdio.h>
using namespace std;

//=============================================================================
// Return:
// 1 = DECLINED
// 2 = INVALID CARD
// 3 = APPROVAL, with Approval Code parameter set
// 4 = ERROR, with error parameter set
// 5 = File does not exist
// 6 = No approval code exists
//=============================================================================
extern "C" _declspec(dllexport)
int viaWarpResponseRead(char* filename, char* approvalCode, char* error)
{
  // Clear output parameters
  *approvalCode = '\0';
  *error = '\0';
 

  // Build filename to read
  stringstream filepath; stringstream filetoDelete;
  //string path = "C:\\Phone\\viaWarp\\PROCESS\\";
  string path = "C:\\Phone\\";
  string fExt = ".OUT";
  std::string fName = std::string(filename);// convert char* filename to string
  fName = fName += ".OUT";
  //string fileToDelete = path +=fName += fExt; //concatenate strings to create filepath with filename
  filepath << "C:\\Phone\\viaWarp\\PROCESS\\" << filename << ".OUT";
  //filepath >> fName;
  // Attempt to open input file
  ifstream inFile(filepath.str().c_str());

  if (!inFile)
  {
    // viaWarp response file does not exist
    strcpy(error, "File not found");
    return 5;
  }

  // Read the whole input file contents
  string contents;//((istreambuf_iterator<char>(inFile)), istreambuf_iterator<char>());
  string line;
  while (getline(inFile, line))
  {
    contents += line + "\n";
  }
      
  // Look for keywords within the file
  int cnt_verbiage = contents.find("verbiage");
  int cnt_approval_code = contents.find("approvalcode");
  int cnt_error = contents.find("error");

  if (cnt_verbiage != string::npos)
  {
    // Look for "DECLINED"
    string sstring = contents.substr(cnt_verbiage + 16, 30);
    bool isDeclined = sstring.find("DECLINED") != string::npos;
    if (isDeclined)
    {
      // Declined credit card
      strcpy(error, "Declined");
      return 1;
    }

    // Look for "INVALID CARD"
    bool isInvalidCard = sstring.find("INVALID CARD") != string::npos;
    if (isInvalidCard)
    {
      // Invalid credit card
      strcpy(error, "Invalid card");
      return 2;
    }

    if (cnt_approval_code != string::npos)
    {
      // Extract the approval code value
      sstring = contents.substr(cnt_approval_code + 20, 30);
      int cnt2 = (sstring.find(">", 1) - 1);
      string codeValue = sstring.substr(0, cnt2);

      // Credit card approved. Send back the approval code
      strcpy(approvalCode, codeValue.c_str());
      return 3;
    }
    else
    {
      // No approval code available
      strcpy(error, "No approval code");
      return 6;
    }
  }

  if (cnt_error != string::npos)
  {
    // Extract the error
    string sstring = contents.substr(cnt_error + 13, 30);
    int cnt2 = (sstring.find(">", 1) - 1);
    string serror = sstring.substr(0, cnt2);

    // Copy error code to output parameter
    strcpy(error, serror.c_str());
  }

  //  error
  return 4;

  remove("C:\\Phone\\viaWarp\\PROCESS\\test.OUT");
}