Exception Thrown: 'System.BadImageFormatException' in xprsdn.dll

I am trying to use XPRESS optimizer using C# using Visual Studio. I found an example which I am trying to run. The code is given below.

using System;
using System.IO;
using Optimizer;
 
namespace XPRSExamples
{
    class MipSolEnum
    {
        static void Main(string[] args)
        {
            XPRS.Init("");
 
            XPRSprob prob = new XPRSprob();
            prob.AddMsgHandlerCallback(Console.Out);
 
            XPRSmipsolpool msp = new XPRSmipsolpool();
            XPRSmipsolenum mse = new XPRSmipsolenum();
 
            prob.MPSFormat = -1;
            prob.ReadProb("hpw15");
            int nCols = prob.Cols;
 
            /* Avoid duplicated solutions from heuristics. */
            msp.DuplicateSolutionsPolicy = 3;
 
            /* Disable dual reductions to prevent dominated solutions from */
            /* being presolved away. */
            prob.MIPDualReductions = 2;
 
            /* Run the enumeration */
            int nMaxSols = 10;
            mse.Minim(prob, msp, XPRSdefaultMipSolEnumHandler.GetDefaultHandlerCallback(), null, ref nMaxSols);
 
            /* Print out the solutions found */
            int nSols = mse.Solutions;
            for (int i = 1; i <= nSols; i++)
            {
                int[] iSolutionId = new int[1];
                double dObj;
                int nSols2, nReturnedSolIds, solutionIdStatus;
                mse.GetSolList((int)XPRSattribute.Mse_Metric_MipObject, i, i, iSolutionId, out nReturnedSolIds, out nSols2);
                mse.GetSolMetric(iSolutionId[0], out solutionIdStatus, (int)XPRSattribute.Mse_Metric_MipObject, out dObj);
                Console.WriteLine("--------\n" + i + " = " + dObj);
                for (int j = 0; j < nCols; j++)
                {
                    double[] dSol = new double[1];
                    int nValuesReturned;
                    msp.GetSol(iSolutionId[0], out solutionIdStatus, dSol, j, j, out nValuesReturned);
                    Console.WriteLine(j + " = " + dSol[0]);
                }
            }
 
            XPRS.Free();
        }
    }
}

I have added the xprsdn.dll in the references. But after running the code, it throws exception

Exception Thrown: 'System.BadImageFormatException' in xprsdn.dll

How do I resolve this?

Thanks!