How to change the transaction level to dirty read in a c++ builder application

Question

I'm trying to follow these steps. It's kinda dated but it seems like this is what I need.

http://www.drbob42.com/examines/examin95.htm

In the DBX4 section, the user did the following in Delphi.

  DBXTransaction := SQLConnection1.BeginTransaction(TDBXIsolations.ReadCommitted);
  try
    // do your work...
    SQLConnection1.CommitFreeAndNil(DBXTransaction);
  except
    SQLConnection1.RollBackFreeAndNil(DBXTransaction);
    raise
  end;

I'm trying to do the same thing in c++

TDBXTransaction* pDBXTransaction;
pDBXTransaction = pDBXSQLConnection->BeginTransaction(xilDIRTYREAD);
try
{
    ClientDataSetList = GetNodesInTree(FReleaseNodeID, SelNodesMasterTbl, lNodesDetailTbl);
    pDBXSQLConnection->CommitFreeAndNil(pDBXTransaction);
}
catch (Exception &E) 
{
    pDBXSQLConnection->RollbackFreeAndNil(pDBXTransaction);
}

However, I'm getting a TDBXError with message 'unassigned code' exception. It seems like I'm missing something but I haven't been able to find a solution online.

I'm using C++ Builder XE 5 And I'm trying to do this through a DBX connection to a Interbase database.