Cannot evaluate expression because a native frame is on top of the call stack on Forms app using odbc

{

locConnToPlan.getWallDataFromPlan();

}

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*** This is the code from the seperate class for the odbc connection:

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Data.Odbc;

using System.Windows.Forms;

namespace ArchiInfo

public class odbcConnect

public string connectionString = "";

public OdbcConnection loadPlan;

private OdbcDataReader sqlReader;

private OdbcCommand sqlCommand;

private string errString = "";

public Char[,] wall_ID = new Char[100,1];

public Char[,] wall_USERID = new Char[100, 1];

public Double[,] wall_LENGTH_SIDE_A = new Double[100, 1];

public Double[,] wall_LENGTH_SIDE_B = new Double[100, 1];

public Double[,] wall_SURFACE_SIDE_A = new Double[100, 1];

public Double[,] wall_SURFACE_SIDE_B = new Double[100, 1];

public Double[,] wall_SURFACE_SIDE_C = new Double[100, 1];

public Double[,] wall_CENTER_LENGTH = new Double[100, 1];

public void connectToPlanFile(string planDirStr, string libDirString)

string connString = "DRIVER={ArchiCAD 11 Project ODBC Driver}; PLANFILE=" + planDirStr + "; LIBRARIES=" + libDirString + "";

loadPlan = new OdbcConnection(connString);

try

catch(OdbcException ex)

errString = "Exception Handled: " + ex.Message;

MessageBox.Show(errString);

return;

public void getWallDataFromPlan()

string sqlQuery = "SELECT id, userid, length_on_sidea, length_on_sideb, surface_on_sidea, surface_on_sideb, surface_on_sidec, center_length FROM walls";

sqlCommand = new OdbcCommand(sqlQuery, loadPlan);

try

catch (OdbcException ex)

errString = "Exception Handled: " + ex.Message;

MessageBox.Show(errString);

return;

try

int rowCounter = 0;

while (sqlReader.Read())

catch (OdbcException ex)

errString = "Exception Handled: " + ex.Message;

MessageBox.Show(errString);

return;

finally