Wcf Rest Service Linq Query Failed with Angular JS Application

I am consuming Wcf REST Service into Angular JS Application. I am Facing some error with the linq Query . I got the follwing error on follwing line on debugging mode ..The underlying provider failed on Commit.

 ReciverAccount.Account_Balance += Convert.ToDecimal(mopneyTransfer.Amount1);
                                dbContextTransaction.Commit();

I ma trying to send money one account to another account and account balance on both account should be updated and insert the respective record into database but i can not do it ..

Here is the Error message on debug Mode .

System.Data.Entity.Core.EntityException occurred
  HResult=0x80131501
  Message=The underlying provider failed on Commit.
  Source=<Cannot evaluate the exception source>
  StackTrace:
<Cannot evaluate the exception stack trace>

Inner Exception 1:
ArgumentNullException: Value cannot be null.

Here is me linq query ..

     public bool MoneyTranfer(MoneyTransfer mopneyTransfer)
    {


        //int amount = System.Convert.ToInt32(mopneyTransfer.Amount);
        //int amount1 = System.Convert.ToInt32(mopneyTransfer.Amount1);


        int ID = Convert.ToInt32(mopneyTransfer.Sender_Account_No);
        var foundAccount = (from a in ctx.Current_Account_Details
                            where a.Account_Number.Equals(ID)
                            select a).Distinct().FirstOrDefault();
        if (foundAccount != null)
        {
            //if (amount > 0)
            //{
            using (var dbContextTransaction = ctx.Database.BeginTransaction())
            {

                    var senderAccount = (from a in ctx.Current_Account_Details
                                         where a.Account_Number.Equals(ID)
                                         select a).Distinct().FirstOrDefault();
                    if (senderAccount != null)
                    {

                        senderAccount.Account_Balance -= Convert.ToDecimal(mopneyTransfer.Amount);
                        dbContextTransaction.Commit();
                        ctx.SaveChanges();
                    }

                    int ID1 = Convert.ToInt32(mopneyTransfer.Receiver_Account_No);

                    var ReciverAccount = (from a in ctx.Current_Account_Details
                                          where a.Account_Number.Equals(ID1)
                                          select a).Distinct().FirstOrDefault();

                    if (ReciverAccount != null)
                    {

                        ReciverAccount.Account_Balance += Convert.ToDecimal(mopneyTransfer.Amount1);
                        dbContextTransaction.Commit();

                        ctx.SaveChanges();
                        Current_Account_Deposit cad = new Current_Account_Deposit();
                        cad.Account_Number = Convert.ToInt32(mopneyTransfer.Sender_Account_No);
                        cad.Account_Holder_Name = mopneyTransfer.Sender_Name;
                        cad.Amount = Convert.ToDecimal(mopneyTransfer.Amount);
                        cad.Sort_Code = mopneyTransfer.Sender_Sort_Code;
                        cad.Transcation_Type = mopneyTransfer.Transcation_Type;
                        cad.Date = mopneyTransfer.Date;
                        ctx.Current_Account_Deposit.Add(cad);

                        ctx.SaveChanges();

                        Current_Account_Withdraw caw = new Current_Account_Withdraw();
                        caw.Account_Number = Convert.ToInt32(mopneyTransfer.Receiver_Account_No);
                        caw.Account_Holder_Name = mopneyTransfer.Receiver_Name;
                        caw.Amount = Convert.ToDecimal(mopneyTransfer.Amount1);
                        caw.Sort_Code = mopneyTransfer.Receiver_Sort_Code;
                        caw.Transcation_Type = mopneyTransfer.Transcation_Type1;
                        caw.Date = mopneyTransfer.Date1;
                        ctx.Current_Account_Withdraw.Add(caw);

                        ctx.SaveChanges();
                    }
                    else
                    {
                        dbContextTransaction.Rollback();
                        return false;
                    }
                }

        }  return false;
    }

Any feedback or suggestion will be great help .