TripleDESCryptoServiceProvider decryption length violation

Question

I am receiving the following error message when attempting to decrypt text: "length of the data to decrypt is invalid" this occurs when I either attempt to flush or close my Cryptostream (I am using a memory stream to store the decrypted text) here is the encrypt/decrypt methods: using System.Security.Cryptography; . . . ///

/// Encrypts text. ///

/// Text to incrypt. /// Encrypted text. public static string Encrypt(string textToEncrypt) { TripleDESCryptoServiceProvider des = new TripleDESCryptoServiceProvider(); des.IV = new byte[8]; PasswordDeriveBytes pdb = new PasswordDeriveBytes(key, new byte[0]); des.Key = pdb.CryptDeriveKey("RC2", "MD5", 128, new byte[8]); MemoryStream ms = new MemoryStream((textToEncrypt.Length * 2)-1); CryptoStream encStream = new CryptoStream(ms, des.CreateEncryptor(),CryptoStreamMode.Write); byte[] plainBytes = Encoding.UTF8.GetBytes(textToEncrypt); encStream.Write(plainBytes, 0, plainBytes.Length); encStream.FlushFinalBlock(); byte[] encryptedBytes = new byte[ms.Length]; ms.Position = 0; ms.Read(encryptedBytes, 0, (int)ms.Length); encStream.Close(); return Convert.ToBase64String(encryptedBytes); } ///

/// Decrypts an encrypted text. ///

/// Text to decrypt. /// Decrypted text. public static string Decrypt(string textToDecrypt) { string rtn; try { TripleDESCryptoServiceProvider des = new TripleDESCryptoServiceProvider(); des.IV = new byte[8]; PasswordDeriveBytes pdb = new PasswordDeriveBytes(key, new byte[0]); des.Key = pdb.CryptDeriveKey("RC2", "MD5", 128, new byte[8]); byte[] encryptedBytes = Convert.FromBase64String(textToDecrypt); MemoryStream ms = new MemoryStream((textToDecrypt.Length*2)); CryptoStream decStream = new CryptoStream(ms, des.CreateDecryptor(),CryptoStreamMode.Write); decStream.Write(encryptedBytes, 0, encryptedBytes.Length); decStream.FlushFinalBlock(); byte[] plainBytes = new byte[ms.Length]; ms.Position = 0; ms.Read(plainBytes, 0, (int)ms.Length); decStream.Close(); rtn = Encoding.UTF8.GetString(plainBytes); } catch (Exception ex) { rtn = ex.Message; } finally { } return rtn; } this was written for me by a contractor who is no longer with us... any help would be GREATLY appreciated!