PaddingMode is undefined

I try to implement the library; the RSA encryption in a project, I copied the example and run the project but don´t work, It show me this error;

TypeError: System.Security.Cryptography.PaddingMode is undefined

This is the code that I used:

	function GetNewRsaProvider(dwKeySize) {
		// Create a new instance of RSACryptoServiceProvider.
		if (!dwKeySize) dwKeySize = 512;
		return new System.Security.Cryptography.RSACryptoServiceProvider(dwKeySize);
	}

	function GetRsaKey(includePrivateParameters) {
		var keyParams = xmlParamsDefault;
		// ------------------------------------------------
		// RSA Keys
		// ------------------------------------------------
		var rsa = GetNewRsaProvider();
		if (keyParams[0] === "<") {
			// Import parameters from xml.
			rsa.FromXmlString(keyParams);
		} else {
			var keyBlob = System.Convert.FromBase64String(keyParams);
			rsa.ImportCspBlob(keyBlob);
		}
		return rsa.ExportParameters(includePrivateParameters);
	}

    function fn_encriptar(Texto, Grifo) {
		var decryptedBytes = System.Text.Encoding.UTF8.GetBytes(Texto);
		var doOaepPadding = false;
		// ------------------------------------------------
		// Encrypt
		// ------------------------------------------------
		var rsa = GetNewRsaProvider();
		// Import the RSA Key information.
		rsa.ImportParameters(GetRsaKey(false));
		// Encrypt the passed byte array and specify OAEP padding.
		var encryptedBytes = rsa.Encrypt(decryptedBytes, doOaepPadding);
		var encryptedString = System.Convert.ToBase64String(encryptedBytes)
		// ------------------------------------------------
		// Display the encrypted data.
		//var encryptedString = System.BitConverter.ToString(encryptedBytes, "");
		return encryptedString;
    }

`